Methods and apparatus for persistent control and protection of content

ABSTRACT

A novel method and apparatus for protection of streamed media content is disclosed. In one aspect, the apparatus includes control means for governance of content streams or content objects, decryption means for decrypting content streams or content objects under control of the control means, and feedback means for tracking actual use of content streams or content objects. The control means may operate in accordance with rules received as part of the streamed content, or through a side-band channel. The rules may specify allowed uses of the content, including whether or not the content can be copied or transferred, and whether and under what circumstances received content may be “checked out” of one device and used in a second device. The rules may also include or specify budgets, and a requirement that audit information be collected and/or transmitted to an external server. In a different aspect, the apparatus may include a media player designed to call plugins to assist in rendering content. A “trust plugin” is disclosed, along with a method of using the trust plugin so that a media player designed for use with unprotected content may render protected content without the necessity of requiring any changes to the media player. In one aspect, the streamed content may be in a number of different formats, including MPEG-4, MP3, and the RMFF format.

RELATED APPLICATIONS

This application is a divisional of U.S. application Ser. No.09/276,233, filed Mar. 25, 1999 now U.S. Pat. No. 7,233,948, which is acontinuation-in-part of U.S. application Ser. No. 09/270,022, filed Mar.16, 1999 (abandoned), both of which are incorporated herein byreference.

FIELD OF THE INVENTION

This invention relates generally to computer and/or electronic security.More particularly, this invention relates to systems and methods forprotection of information in streamed format.

BACKGROUND

Streaming digital media consists generally of sequences of digitalinformation received in a “stream” of packets, and designed to bedisplayed or rendered. Examples include streamed audio content, streamedvideo, etc.

Digital media streams are becoming an increasingly significant means ofcontent delivery, and form the basis for several adopted, proposed or defacto standards. The acceptance of this format, however, has beenretarded by the ease with which digital media streams can be copied andimproperly disseminated, and the consequent reluctance of content ownersto allow significant properties to be distributed through streamingdigital means. In addition, the lack of a common format for carryingsecurity and rights management information that is flexible enough toaccommodate arbitrary content formats and functions has madeinteroperability more difficult. For these reasons, there is a need fora methodology by which digital media streams can be protected.

SUMMARY OF THE INVENTION

Consistent with the invention, this specification describes newarchitectures for protection of information provided in streamed format.One such architecture is described in the context of a generic systemwhich resembles a system to render content encoded pursuant to theMPEG-4 specification (ISO/IEC 14496.1), though with certainmodifications, and with the proviso that the described system may differfrom the MPEG-4 standard in certain respects. A variety of differentarchitecture embodiments are also described, including an MPEG-4embodiment, a system designed to render content encoded pursuant to theMP3 specification (ISO/IEC TR 11172), and an embodiment which isadvantageous in the context of limited resource content devices.

According to aspects of the invention, these architectures involvesystem design aspects and information format aspects. System designaspects include the incorporation of content protection functionality,control functionality, and feedback enabling control functionality tomonitor the activities of the system. Information format aspects includethe incorporation of rule/control information into information streams,and the protection of content through mechanisms such as encryption andwatermarking.

Systems and methods consistent with the present invention performcontent protection and digital rights management. A streaming mediaplayer consistent with the present invention includes a port designed toaccept a digital bit stream. The digital bit stream includes content,which is encrypted at least in part, and a secure container includingcontrol information designed to control use of the content, including atleast one key suitable for decryption of at least a portion of thecontent. The media player also includes a control arrangement includinga means for opening secure containers and extracting cryptographic keys,and means for decrypting the encrypted portion of the content.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute apart of this specification, illustrate an embodiment of the inventionand, together with the description, serve to explain the advantages andprinciples of the invention. In the drawings,

FIG. 1 shows a generic system consistent with the present invention;

FIG. 2 shows an exemplary Header 201 consistent with the presentinvention;

FIG. 3 shows a general encoding format consistent with the presentinvention;

FIG. 4 illustrates one manner for storing a representation of a workconsistent with the present invention;

FIG. 5 shows an example of a control message format;

FIG. 6 is a flow diagram illustrating one embodiment of the steps whichtake place using the functional blocks of FIG. 1;

FIG. 7 illustrates a form wherein the control messages may be stored inControl Block 13;

FIG. 8 shows MPEG-4 System 801 consistent with the present invention;

FIG. 9 shows an example of a message format;

FIG. 10 illustrates an IPMP table consistent with the present invention;

FIG. 11 illustrates a system consistent with the present invention;

FIG. 12 illustrates one embodiment of the DigiBox format;

FIG. 13 shows an example of a Real Networks file format (RMFF);

FIG. 14 shows an RNPFF format consistent with the present invention;

FIG. 15 illustrates the flow of changes to data in the Real Networksfile format in an architecture consistent with the present invention;

FIG. 16 illustrates a standard Real Networks architecture;

FIG. 17 shows an exemplary architecture in which a trust plugin operateswithin the overall Real Networks architecture;

FIG. 18 shows a bit stream format consistent with the principles of thepresent invention;

FIG. 19 shows one embodiment of protection applied to the MP3 format;

FIG. 20 illustrates one embodiment of an MP3 player designed to processand render protected content;

FIG. 21 illustrates the flow of data in one embodiment in which aprotected MPEG-4 file may be created consistent with the presentinvnetion;

FIG. 22 illustrates the flow of data in one embodiment in which controlmay be incorporated into an existing MPEG-4 stream consistent with thepresent invention;

FIG. 23 shows a system consistent with the principles of the presentinvention;

FIG. 24 shows a system consistent with the principles of the presentinvention;

FIG. 25 shows an example of an aggregate stream consistent with thepresent invention;

FIG. 26 illustrates a Header CMPO 2601 consistent with the presentinvention;

FIG. 27 shows exemplary Content Management Protection Objects consistentwith the principles of the present invention;

FIG. 28 shows an example of a CMPO Data Structure 2801 consistent withthe present invention;

FIG. 29 discloses an illustrative environment for the securedistribution of digital content;

FIG. 30 shows one method for downloading digital or other content from acontrol module to a content player;

FIG. 31 sets forth, in accordance with the invention, one exemplary fileformat for distributing content; and

FIG. 32 sets forth yet another exemplary file format for distributingcontent.

DETAILED DESCRIPTION

Reference will now be made in detail to implementations consistent withthe principles of the present invention as illustrated in theaccompanying drawings.

The following U.S. patents and applications, each of which is assignedto the assignee of the current application, are hereby incorporated intheir entirety by reference: Ginter, et al., “Systems and Methods forSecure Transaction Management and Electronic Rights Protection,” U.S.patent application Ser. No. 08/964,333, filed on Nov. 4, 1997 (“Ginter'333”); Ginter, et al., “Trusted Infrastructure Support Systems, Methodsand Techniques for Secure electronic commerce, Electronic Transactions,Commerce Process Control Automation, Distributed Computing, and RightsManagement,” U.S. patent application Ser. No. 08/699,712, filed on Aug.12, 1996 (“Ginter '712”); Van Wie, et al, “Steganographic Techniques forSecurely Delivering Electronic Digital Rights Management InformationOver Insecure Communications Channels, U.S. patent application Ser. No.08/689,606, filed on Aug. 12, 1996 (“Van Wie”); Ginter, et. al “SoftwareTamper Resistance and Secure Communication,” U.S. patent applicationSer. No. 08/706,206, filed on Aug. 30, 1996 (“Ginter, '206”); Shear, etal, “Cryptographic Methods, Apparatus & Systems for Storage MediaElectronic Rights Management in Closed & Connected Appliances,” U.S.patent application Ser. No. 08/848,077, filed on May 15, 1997 (“Shear”);Collberg et al, “Obfuscation Techniques for Enhancing SoftwareSecurity,” U.S. patent application Ser. No. 09/095,346, filed on Jun. 9,1998 (“Collberg”); Shear, “Database Usage Metering and Protection Systemand Method,” U.S. Pat. No. 4,827,508, issued on May 2, 1989 (“ShearPatent”).

FIG. 1 illustrates Media System 1, which is capable of accepting,decoding, and rendering streamed multimedia content. This is a genericsystem, though it includes elements based on the MPEG-4 specification.Media System 1 may include software modules, hardware (includingintegrated circuits) or a combination. In one embodiment, Media System 1may include a Protected Processing Environment (PPE) as described in theGinter '333 application.

In FIG. 1, Bit Stream 2 represents input information received by System1. Bit Stream 2 may be received through a connection to an externalnetwork (e.g., an Internet connection, a cable hookup, radiotransmission from a satellite broadcaster, etc.), or may be receivedfrom a portable memory device, such as a DVD player.

Bit Stream 2 is made up of a group of related streams of information,including Organization Stream 3, Audio Stream 4, Video Stream 5, ControlStream 6, and Info Stream 31. Each of these streams is encoded into theoverall Bit Stream 2. Each of these represents a category of streams, sothat, for example, Video Stream 5 may be made up of a number of separateVideo Streams.

These streams correspond generally to streams described in the MPEG-4format as follows:

Organization Stream 3 corresponds generally to the BIFS stream and theOD (“Object Descriptor”) stream.

Audio Stream 4 and Video Stream 5 correspond generally to the Audio andVideo streams.

Control Stream 6 corresponds generally to the IPMP stream.

Audio Stream 4 includes compressed (and possibly encrypted) digitalaudio information. This information is used to create the sound renderedand output by Media System 1. Audio Stream 1 may represent multipleaudio streams. These multiple streams may act together to make up theaudio output, or may represent alternative audio outputs.

Video Stream 5 includes compressed (and possibly encrypted) digitalvideo information. This information is used to create the images andvideo rendered and output by Media System 1. Video Stream 5 mayrepresent multiple video streams. These multiple streams may acttogether to make up the video output, or may represent alternative videooutputs.

Organization Stream 3 includes organizational information and metadatarelated to the work to be rendered. This information may include a treeor other organizational device which groups audio and video streams intoobjects. This information may also include metadata associated with theentire work, the objects, or the individual streams.

Control Stream 6 includes control information, divided generally intoheader information and messages. The header information includes anidentifier for each discrete message. The content of the messages, whichwill be described further below, may include cryptographic keys andrules governing the use of content.

Info Stream 31 carries additional information associated with thecontent in other components of Bit Stream 2, including but not limitedto graphics representing cover art, text for lyrics, coded sheet musicor other notation, independent advertising content, concert information,fan club information, and so forth. Info Stream 31 can also carry systemmanagement and control information and/or components, such as updates tosoftware or firmware in Media System 1, algorithm implementations forcontent-specific functions such as watermarking, etc.

Each of these streams is made up of packets of information. In oneexemplary embodiment, each packet is 32 bytes in length. Since a singlecommunications channel (e.g., a cable, a bus, an infrared or radioconnection) contains packets from each of the streams, packets need tobe identified as belonging to a particular stream. In a preferredembodiment, this is done by including a header which identifies aparticular stream and specifies the number of following packets whichare part of that stream. In another embodiment, each packet may includeindividual stream information.

Exemplary Header 201 is shown in FIG. 2. This header may generally beused for the Organization, Audio and Video Streams. A header for theControl Stream is described below. Header 201 includes Field 202, whichincludes a bit pattern identifying Header 201 as a header. Field 203identifies the particular type of stream (e.g., Audio Stream,Organization Stream, Control Stream, etc.) Field 204 contains anElementary Stream Identifier (ES_ID), which is used to identify theparticular stream, and may be used in cases where multiple streams of aparticular stream type may be encountered at the same time. Field 207contains a time stamp, which is used by the system to synchronize thevarious streams, including rendering of the streams. Composite Block 11may, for example, keep track of the elapsed time from the commencementof rendering. Time Stamp 207 may be used by Composite Block 11 todetermine when each object is supposed to be rendered. Time Stamp 207may therefore specify an elapsed time from commencement of rendering,and Composite Block 11 may use that elapsed time to determine when torender the associated object.

Field 205 contains a Governance Indicator. Field 206 identifies thenumber of following packets which are part of the identified stream. Ineach case, the relevant information is encoded in a binary format. Forexample, Field 202 might include an arbitrary sequence of bits which isrecognized as indicating a header, and Field 203 might include two bits,thereby allowing encoding of four different stream types.

Returning to FIG. 1, System 1 includes Demux 7, which accepts as inputBit Stream 2 and routes individual streams (sometimes referred to asElementary. Streams or “ESs”) to appropriate functional blocks of thesystem.

Bit Stream 2 may be encoded in the format illustrated in FIG. 3. In thisfigure, Header 301 is encountered in the bit stream, with Packet 302following, and so on through Packet 308.

When Demux 7 encounters Header 301, Demux 7 identifies Header 301 as aheader and uses the header information to identify Packets 302-305 asorganization stream packets. Demux 7 uses this information to routethese packets to Organization Block 8. Demux 7 handles Header 306 in asimilar manner, using the contained information to route Packets 307 and308 to AV (“Audio Video”) Block 9.

AV Block 9 includes Decompressor 10, which accepts Elementary Streamsfrom Audio Stream 4 and Video Stream 5 and decompresses those streams.As decompressed, the stream information is placed in a format whichallows it to be manipulated and output (through a video display,speakers, etc.). If multiple streams exist (e.g., two video streams eachdescribing an aspect of a video sequence), AV Block 9 uses the ES_ID toassign each packet to the appropriate stream.

Organization Block 8 stores pointer information identifying particularaudio streams and video streams contained in a particular object, aswell as metadata information describing, for example, where the objectis located, when it is to be displayed (e.g., the time stamp associatedwith the object), and its relationship to other objects (e.g., is onevideo object in front of or behind another video object). Thisorganization may be maintained hierarchically, with individual streamsrepresented at the lowest level, groupings of streams into objects at ahigher level, complete scenes at a still higher level, and the entirework at the highest level.

FIG. 4 illustrates one manner in which Organization Block 8 may store arepresentation of a work. In this Figure, Tree 401 represents an entireaudiovisual work. Branch 402 represents a high-level organization of thework. This may include, for example, all of the video or possibly theaudio and video associated with a particular scene.

Sub-Branch 403 represents a group of related video objects. Each suchobject may include an entire screen, or an individual entity within thescreen. For example, Sub-Branch 403 may represent a background whichdoes not change significantly from one shot to the next. If the video ismoving between two points of reference (e.g., a conversation, with thecamera point of view changing from one face to the other), Sub-Branch404 could represent a second background, used in the second point ofview.

Nodes 405 and 406 may represent particular video objects containedwithin the related group. Node 405 could, for example, represent adistant mountain range, while Node 406 represents a tree immediatelybehind one of the characters.

Each of the nodes specifies or contains a particular ES_ID, representingthe stream containing the information used by that node. Node 405, forexample, contains ES_ID 407, which identifies a particular video streamwhich contains compressed (and possibly encrypted) digital informationrepresenting the mountain range.

Composite Block 11 accepts input from Organization Block 8 and from AVBlock 9. Composite Block 11 uses the input from Organization Block 8 todetermine which specific audiovisual elements will be needed at anygiven time, and to determine the organization and relationship of thoseelements. Composite Block 11 accepts decompressed audiovisual objectsfrom AV Block 9, and organizes those objects as specified by informationfrom Organization Block 8. Composite Block 11 then passes the organizedinformation to Rendering Device 12, which might be a television screen,stereo speakers, etc.

Control Block 13 stores control messages which may be received throughControl Stream 6 and/or may be watermarked into or steganographicallyencoded in other streams, including Audio Stream 4 and Video Stream 5.One control message format is illustrated by FIG. 5, which shows ControlMessage 501. Control Message 501 is made up of Header 502 and Message503. Header 502 consists of Field 508, which includes a bit patternidentifying the following information as a header; Stream Type Field509, which identifies this as a header for the organization stream; IDField 504, which identifies this particular control message; PointerField 505, which identifies those ESs which are controlled by thismessage; Time Stamp Field 507, which identifies the particular portionof the stream which is controlled by this control message (this mayindicate that the entirety of the stream is controlled); and LengthField 506, which specifies the length (in bytes) of Message 503. Message503 may include packets following Header 502, using the general formatshown in FIG. 3. In the example shown, Control Message 501 carries theunique ID 111000, encoded in ID Field 504. This control message controlsESs 14 and 95, as indicated by Pointer Field 505. The associated Messagecontains 1,024 bytes, as indicated by Length Field 506.

In an alternate embodiment, the association of control to content may bemade in Organization Block 8, which may store a pointer to particularcontrol messages along with the metadata associated with streams,objects, etc. This may be disadvantageous, however, in that it may bedesirable to protect this association from discovery or tampering byusers. Since Control Block 13 will generally have to be protected in anyevent, storing the association in this block may make protection ofOrganization Block 8 less necessary.

Control Block 13 implements control over System 1 through Control Lines14, 15 and 16, which control aspects of Organization Block 8, AV Block 9and Composite Block 11, respectively. Each of these Control Lines mayallow two-way communication.

Control Lines 14 and 15 are shown as communicating with AV Block StreamFlow Controller 18 and with Organization Block Stream Flow Controller17. These Stream Flow Controllers contain functionality controlled byControl Block 13. In the embodiment illustrated, the Stream FlowControllers are shown as the first stage in a two-stage pipeline, withinformation being processed by the Stream Flow Controller and thenpassed on to the associated functional block. This allows isolation ofthe control functionality from the content manipulation and displayfunctionality of the system, and allows control to be added in withoutaltering the underlying functionality of the blocks. In an alternateembodiment, the Stream Flow Controllers might be integrated directlyinto the associated functional blocks.

Stream Flow Controllers 17 and 18 contain Cryptographic Engines 19 and20, respectively. These Cryptographic Engines operate under control ofControl Block 13 to decrypt and/or cryptographically validate (e.g.,perform secure hashing, message authentication code, and/or digitalsignature functions) the encrypted packet streams received from Demux 7.Decryption and validation may be selective or optional according to theprotection requirements for the stream.

Cryptographic Engines 19 and 20 may be relatively complex, and may, forexample, include a validation calculator that performs cryptographichashing, message authentication code calculation, and/or othercryptographic validation processes. In addition, as is described furtherbelow, additional types of governance-related processing may also beused. In one alternative embodiment, a single Stream Flow Controller maybe used for both Organization Stream 3 and Audio/Video Streams 4-5. Thismay reduce the cost of and space used by System 1. These reductions maybe significant, since System 1 may contain multiple AV Blocks, eachhandling a separate Audio or Video Stream in parallel. This alternativemay, however, impose a latency overhead which may be unacceptable in areal-time system.

If the Stream Flow Controllers are concentrated in a single block, theymay be incorporated directly into Demux 7, which may handle governanceprocessing prior to routing streams to the functional blocks. Such anembodiment would allow for governed decryption or validation of theentirety of Bit Stream 2, which could occur prior to the routing ofstreams to individual functional blocks. Encryption of the entirety ofBit Stream 2 (as opposed to individual encryption of individual ESs)might be difficult or impossible without incorporating stream controllerfunctionality into Demux 7, since Demux 7 might otherwise have noability to detect or read the header information necessary to routestreams to functional blocks (that header information presumably beingencrypted).

As is noted above, each of the individual streams contained in BitStream 2 may be individually encrypted. An encrypted stream may beidentified by a particular indicator in the header of the stream, shownin FIG. 2 as Governance Indicator 205.

When a header is passed by Demux 7 to the appropriate functional block,the stream flow controller associated with that block reads the headerand determines whether the following packets are encrypted or otherwisesubject to governance. If the header indicates that no governance isused, the stream flow controller passes the header and the packetsthrough to the functional blocks with no alteration. GovernanceIndicator 205 may be designed so that conventionally encoded content(e.g., unprotected MPEG-4 content) is recognized as having no GovernanceIndicator and therefore passed through for normal processing.

If a stream flow controller detects a set governance indicator, itpasses the ES_ID associated with that stream and the time stampassociated with the current packets to Control Block 13 along ControlLine 14 or 15. Control Block 13 then uses the ES_ID and time stampinformation to identify which control message(s) are associated withthat ES. Associated messages are then invoked and possibly processed, asmay be used for governance purposes.

A simple governance case is illustrated by FIG. 6, which shows stepswhich take place using the functional blocks of FIG. 1. In Step 601,Demux 7 encounters a header, and determines that the header is part ofthe AV stream. In Step 602, Demux 7 passes the header to AV StreamController 18. In Step 603, AV Stream Controller 18 reads the header anddetermines that the governance indicator is set, thereby triggeringfurther processing along Path 604. In Step 605, AV Stream Controller 18obtains the ES_ID and time stamp from the header and transmits these toControl Block 13, along Control Line 15. In Step 606, Control Block 13,looks up the ES_ID and determines that the ES_ID is associated with aparticular control message. In Step 611, Control Block 13 uses the timestamp information to choose among control messages, if there is morethan one control message associated with a particular ES. In Step 607,Control Block 13 accesses the appropriate control message, and obtains acryptographic key or keys for decryption and/or validation. In Step 608,Control Block 13 passes the cryptographic key(s) along Control Line 15to AV Stream Controller 18. In Step 609, AV Stream Controller 18 usesthe cryptographic key as an input to Cryptographic Engine 20, whichdecrypts and/or validates the packets following the header as thosepackets are received from Demux 7. In Step 610, the decrypted packetsare then passed to AV Block 9, which decompresses and processes them ina conventional manner.

Time stamp information may be useful when it is desirable to change thecontrol message applicable to a particular ES. For example, it may beuseful to encode different portions of a stream with different keys, sothat an attacker breaking one key (or even a number of keys) will not beable to use the content. This can be done by associating a number ofcontrol messages with the same stream, with each control message beingvalid for a particular period. The time stamp information would then beused to choose which control message (and key) to use at a particulartime. Alternatively, one control message may be used, but with updatedinformation being passed in through the Control Stream, the updatesconsisting of a new time stamp and a new key.

In an alternative embodiment, Control Block 13 may proactively send theappropriate keys to the appropriate stream flow controller by using timestamp information to determine when a key will be will be needed. Thismay reduce overall latency.

Control Line 16 from FIG. 1 comes into play once information has beenpassed from Organization Block 8 and AV Block 9 to Composite Block 11,and the finished work is prepared for rendering through Rendering Device12. When Composite Block 11 sends an object to Rendering Device 11,Composite Block 11 sends a start message to Control Block 13. Thismessage identifies the object (including any associated ES_IDs), andspecifies the start time of the display (or other rendering) of thatobject. When an object is no longer being rendered, Composite Block 11sends an end message to Control Block 13, specifying that rendering ofthe object has ended, and the time at which the ending occurred.Multiple copies of a particular object may be rendered at the same time.For this reason, start and stop messages sent by Composite Block 11 mayinclude an assigned instance ID, which specifies which instance of anobject is being rendered.

Control Block 13 may store information relating to start and stop timesof particular objects, and/or may pass this information to externaldevices (e.g., External Server 30) through Port 21. This informationallows Control Block 13 to keep track not only of which objects havebeen decrypted, but of which objects have actually been used. This maybe used, since System 1 may decrypt, validate, and/or decompress manymore objects than are actually used. Control Block 13 can also determinethe length of use of objects, and can determine which objects have beenused together. Information of this type may be used for sophisticatedbilling and auditing systems, which are described further below.

Control Line 16 may also be used to control the operation of CompositeBlock 11. In particular, Control Block 13 may store informationspecifying when rendering of a particular object is valid, and may keeptrack of the number of times an object has been rendered. If ControlBlock 13 determines that an object is being rendered illegally (i.e., inviolation of rules controlling rendering), Control Block 13 mayterminate operation of Composite Block 11, or may force erasure of theillegal object.

In an alternate embodiment, the level of control provided by ControlLine 16 may at least in part be provided without requiring the presenceof that line. Instead, Control Block 13 may store a hash of theorganization information currently valid for Organization Block 8. Thishash may be received through Control Stream 6, or, alternatively, may begenerated by Control Block 13 based on the information contained inOrganization Block 8.

Control Block 13 may periodically create a hash of the informationcurrently resident in Organization Block 8, and compare that to thestored hash. A difference may indicate that an unauthorized alterationhas been made to the information in Organization Block 8, therebypotentially allowing a user to render information in a manner violativeof the rules associated with that information. In such an event, ControlBlock 13 may take appropriate action, including deleting the informationcurrently resident in Organization Block 8.

If System 1 is designed so that Organization Block 8 controls the use ofcontent by Composite Block 11, so that content cannot be rendered exceptas is specified by the organization information, Control Block 13 may beable to control rendering of information through verifying that thecurrent Organization Block contents match the hash which has beenreceived by Control Block 13, thereby eliminating at least one reasonfor the presence of Control Line 16.

Control Block 13 may also be responsible for securely validating theorigin, integrity, authenticity, or other properties of receivedcontent, through cryptographic validation means such as secure hashing,message authentication codes, and/or digital signatures.

System 1 may also include an Inter-Rights Point, indicated as IRP 22.IRP 22 is a protected processing environment (e.g., a PPE) in whichrules/controls may be processed, and which may store sensitiveinformation, such as cryptographic keys. IRP 22 may be incorporatedwithin Control Block 13, or may be a separate module. As is illustrated,IRP 22 may include CPU 23 (which can be any type of processing unit),Cryptographic Engine 24, Random Number Generator 25, Real Time Clock 26,and Secure Memory 27. In particular embodiments, some of these elementsmay be omitted, and additional functionality may be included.

Governance Rules

Control messages stored by Control Block 13 may be very complex. FIG. 7illustrates the form in which the control messages may be stored inControl Block 13, consisting of Array 717. Column 701 consists of theaddress at which the control messages are stored. Column 702 consists ofthe identifier for each control message. This function may be combinedwith that of Column 701, by using the location information of Column 701as the identifier, or by storing the message in a location whichcorresponds to the identifier. Column 703 consists of the ES_IDs foreach stream controlled by the control message. Column 704 consists ofthe message itself. Thus, the control message stored at location 1 hasthe ID 15, and controls stream 903.

In a simple case, the message may include a cryptographic key, used todecrypt the content associated with the stream(s) controlled by themessage. This is illustrated by Cryptographic Key 705 from FIG. 7.Cryptographic keys and/or validation values may also be included topermit cryptographic validation of the integrity or origin of thestream.

In a more complex case, the message may include one or more rulesdesigned to govern access to or use of governed content. Rules may fallinto a number of categories.

Rules may require that a particular aspect of System 1, or a user ofSystem 1, be verified prior to decryption or use of the governedcontent. For example, System 1 may include System ID 28, which stores aunique identifier for the system. A particular rule contained in acontrol message may specify that a particular stream can only bedecrypted on a system in which System ID 28 contains a particular value.This is illustrated at row 2 in FIG. 7, in which the message is shown asconsisting of a rule and commands. The rule may be implicit, andtherefore may not be stored explicitly in the table (e.g. the table maystore only the rule, the rule—specific functions (commands) invoked bythe rule, or only the functions).

In this case, when Stream Controller 18 encounters a Header for stream2031 containing a set governance indicator, Stream Controller 18 passesthe associated ES_ID (2031) to Control Block 13. Control Block 13 thenuses the ES_ID to identify Control Message 20 which governs stream 2031.Control Message 20 includes Rule 706, which includes (or invokes)Commands 707, and an Authorized System ID 708. Authorized System ID 708may have been received by System 1, either as part of Control Message20, or as part of another control message (e.g., Control Message 9),which Control Message 20 could then reference in order to obtain accessto the Authorized System ID. Such a case might exist, for example, if acable subscriber had pre-registered for a premium show. The cable systemmight recognize that registration, and authorize the user to view theshow, by sending to the user an ID corresponding to the System ID.

When Rule 706 is invoked, corresponding Commands 707 access System ID 28and obtain the system ID number. The commands then compare that numberto Authorized System ID 708, specified by Rule 706. If the two numbersmatch, Commands 707 release Cryptographic Key 709 to Stream Controller18, which uses Cryptographic Key 709 to decrypt the stream correspondingto ES_ID 2031. If the two numbers do not match, Commands 707 fail torelease Cryptographic Key 709, so that Stream Controller 18 is unable todecrypt the stream.

In order to carry out these functions, in one embodiment, Control Block13 includes, or has access to, a processing unit and memory. Theprocessing unit is preferably capable of executing any of the commandswhich may be included or invoked by any of the rules. The memory willstore the rules and association information (ID of the control messageand IDs of any governed ESs).

Since the functions being carried out by Control Block 13 are sensitive,and involve governance of content which may be valuable, Control Block13 may be partially or completely protected by a barrier which resiststampering and observation. As is described above, the processing unit,secure memory, and various other governance-related elements may becontained in IRP 22, which may be included in or separate from ControlBlock 13.

Control Block 13 may also carry out somewhat more complex operations. Inone example, a control message may require that information from System1 not only be accessed and compared to expected information, but storedfor future use. For example, a control message might allow decryption ofa Stream, but only after System ID 28 has been downloaded to and storedin Control Block 13. This would allow a control message to check thestored System ID against System ID 28 on a regular basis, or perhaps onevery attempted re-viewing of a particular Stream, thereby allowing thecontrol message to insure that the Stream is only played on a singleSystem.

Control Block 13 may also obtain information dynamically. For example,System 1 may include User Interface 29, which can include any type ofuser input functionality (e.g., hardware buttons, information displayedon a video screen, etc.) A particular rule from a control message mayrequire that the user enter information prior to allowing decryption oruse of a stream. That information may, for example, be a password, whichthe Rule can then check against a stored password to insure that theparticular user is authorized to render the stream.

Information obtained from the user might be more complicated. Forexample, a rule might require that the user input payment or personalinformation prior to allowing release of a cryptographic key. Paymentinformation could, for example, constitute a credit card or debit cardnumber. Personal information could include the user's name, age,address, email address, phone number, etc. Entered information couldthen be sent through Port 21 to External Server 30 for verification.Following receipt of a verification message from External Server 30, theRule could then authorize release of a cryptographic key. Alternatively,Control Block 13 may be designed to operate in an “off-line” mode,storing the information pending later hookup to an external device (ornetwork). In such a case, Control Block 13 might require that aconnection be made at periodic intervals, or might limit the number ofauthorizations which may be obtained pending the establishment of anexternal connection.

In a somewhat more complex scenario, a control message may includeconditional rules. One particular example is illustrated by row 4 of thetable shown in FIG. 7, in which Control Message 700 is shown ascontrolling streams 49-53. Control Message 700 further consists of Rule710, Commands 711 and Cryptographic Keys 712-716. There could, ofcourse, be a number of additional cryptographic keys stored with themessage.

In this case, Rule 710 specifies that a user who agrees to pay a certainamount (or provide a certain amount of information) may view Stream 49,but all other users are required to view Stream 50, or a combination ofStreams 49 and 50. In this case, Stream 49 may represent a movie ortelevision program, while Stream 50 represents advertisements. In oneembodiment, different portions of Stream 49 may be decrypted withdifferent keys so that, for example, a first portion is decrypted withKey 712, a second portion is decrypted with Key 713, a third portion isdecrypted with Key 714, and so on. Rule 710 may include all keys used todecrypt the entirety of Stream 49. When the user initially attempts toaccess the video encoded in Stream 49, Rule 710 could put up a messageasking if the user would prefer to use pay for view mode or advertisingmode. If the user selects pay for view mode, Rule 710 could store (ortransmit) the payment information, and pass Cryptographic Key 712 toStream Controller 18. Stream Controller 18 could use Cryptographic Key712 to decrypt the first stream until receipt of a header indicatingthat a different key is needed to decrypt the following set of packets.Upon request by Stream Controller 18, Control Block 13 would then checkto determine that payment had been made, and then release CryptographicKey 713, which would be used to decrypt the following packets, and soon. Rule 710 could additionally release Cryptographic Key 716,corresponding to Organization Stream 52, which corresponds to videowithout advertisements.

If, on the other hand, the user had chosen the advertising mode, Rule710 could release Cryptographic Key 712 to Stream Controller 18 to allowdecryption of Stream 49. Rule 710 could also authorize decryption ofStream 50 which contains the advertisements. Rule 70 could furtherrelease Cryptographic Key 715 to Organization Block 8. Cryptographic Key715 matches Organization Stream 51. Organization Stream 51 referencesthe video from Stream 49, but also references advertisements from Stream50. Rule 710 would refuse to release Cryptographic Key 716, whichcorresponds to Organization Stream 52, which corresponds to the videowithout advertisements.

In operation, Control Block 13 could monitor information from CompositeBlock 11 over Control Line 16. That information could include theidentity of each object actually rendered, as well as a start and stoptime for the rendering. Control Block 13 could use this information todetermine that an advertisement had actually been rendered, prior toreleasing Cryptographic Key 713 for decryption of the second portion ofvideo from Stream 49. This feedback loop allows Control Block 13 to becertain that the advertisements are not only being decrypted, but arealso being displayed. This may be necessary because Composite Block 11may be relatively unprotected, thereby allowing an unscrupulous user toremove advertisements before viewing.

A variety of additional relatively complex scenarios are possible. Forexample, rules from Control Block 13 could customize the programming fora particular geographic location or a particular type of viewer, byusing information on the location or the viewer to control conditionaldecryption or use. This information could be stored in System 1 orentered by the user.

In another example, shown at row 5 of Array 717, Rule 719 may specifyBudget 718, which may include information relating to the number of usesavailable to the user, the amount of money the user has to spend, etc.In operation, Rule 719 may require that Budget 718 be securely storedand decremented each time a budgeted activity occurs (e.g., each timethe associated work is played). Once the budget reaches zero, Rule 719may specify that the work may no longer be played, or may display amessage to the user indicating that the user may obtain additionalbudget by, for example, entering a credit card number or password, orcontacting an external server.

In another example, a rule may control the ability of a user to copy awork to another device. The rule may, for example, specify that the useris authorized to use the governed work on more than one device, but withonly one use being valid at any time. The rule may specify that anindication be securely stored regarding whether the user has “checkedout” the work. If the user copies the work to another device (e.g.,through Port 21), the rule may require that the work only be transmittedin encrypted form, and that the relevant control messages be transmittedalong with it. The rule can further require that an indicator besecurely set, and that the indicator be checked each time the userattempts to use or copy the work. If the indicator is set, the rulemight require that the work not be decrypted or used, since the useronly has the right to use the work on one device at a time, and theindicator establishes that the work is currently “checked out” toanother device and has not been checked back in.

The receiving device may include the same type of indicator, and mayallow the user to use the work only as long as the indicator is not set.If the user desires to use the'work on the original device, the twodevices may communicate, with the indicator being set in the second andreset in the first. This allows the work to be stored in two locations,but only used in one.

In another embodiment, the same result may be reached by copying therelevant control message from one device to the other, then erasing itfrom the original device. Because the control message includes keys usedfor decryption, this would insure that the work could only be used inone device at a time.

In one embodiment, this technique may be used to communicate digitalmedia files (e.g., music, video, etc.) from a personal computer to aconsumer electronics device without allowing the user to make multiplechoices for simultaneous use. Thus, a larger, more sophisticated device(e.g., a personal computer), could download a file, then “check out” thefile to a portable device lacking certain functions present in thepersonal computer (e.g., a hand-held music player).

Rules may also be used to specify that an initial user may transfer thefile to another user, but only by giving up control over the file. Suchrules could operate similarly to the technique described above fortransferring a file from one device to another, or could require thatthe original file be entirely erased from the original device after thetransfer.

Rules in Control Block 13 may be added or updated through at least twochannels. New rules may be obtained through Control Stream 6. If acontrol message contains an identifier corresponding to a controlmessage already present in Control Block 13, that control message(including contained rules) may overwrite the original control message.A new rule may, for example, be identical to an existing rule, but witha new time stamp and new keys, thereby allowing decryption of a streamwhich had been encrypted with multiple keys. System 1 may be designed sothat certain rules may not be overwritable. This may be enforced bydesignating certain positions in Array 717 as non-overwritable, or byproviding a flag or other indicator to show that a particular rulecannot be overwritten or altered. This would allow for certain types ofsuperdistribution models, including allowing a downstream distributor toadd rules without allowing the downstream distributor to remove or alterthe rules added by upstream distributors.

In addition, new rules may be encoded into Organization Stream 3, AudioStream 4, or Video Stream 5, in the form of a watermark orsteganographic encoding.

New rules may also be obtained through Port 21. Port 21 may connect toan external device (e.g., a smart card, portable memory, etc.) or mayconnect to an external network (e.g., External Server 30). Rules may beobtained through Port 21 either in an ad hoc manner, or as a result ofrequests sent by Control Block 13. For example, Control Message 14 (FIG.7, row 6) may include a rule specifying that a new rule be downloadedfrom a particular URL, and used to govern Stream 1201.

Control messages, including rules, may be encoded using securetransmission formats such as DigiBoxes. A DigiBox is a secure containermeans for delivering a set of business rules, content descriptioninformation, content decryption information and/or content validationinformation. One or more DigiBoxes can be placed into the headers of themedia content or into data streams within the media.

FIG. 12 illustrates one embodiment of the DigiBox format and the mannerin which that format is incorporated into a control message. ControlMessage 1201 is made up of Control Message Header 1202 and ControlMessage Contents 1203. As is described elsewhere, Control Message Header1202 may include information used by Demux 7 (FIG. 1) to appropriatelyroute the message to Control Block 13.

Control Message Contents 1203 of Control Message 1201 consists ofDigiBox 1204, and may also include additional information. DigiBox 1204consists of DigiBox Header 1205, Rules 1206 and Data 1207. Rules 1206may include one or more rules. Data 1207 may include various types ofdata, including ES_ID 1208, Cryptographic Key 1209, and Validation Data1210. Data 1207 may also include cryptographic information such as aspecification of the encryption algorithm, chaining modes used with thealgorithm, keys and initialization vectors used by the decryption andchaining.

Initialization vectors contained within Data 1207 are similar tocryptographic keys, in that they constitute input to the originalencryption process and therefore are necessary for decryption. In onewell-known prior art embodiment, the initialization vectors may begenerated by starting with a base initialization vector (a 64 bit randomnumber) and xor'ing in the frame number or start time for the contentitem.

Validation Data 1210 contained within Data 1207 may includecryptographic has or authentication values, cryptographic keys forcalculating keyed authentication values (e.g., message authenticationcodes), digital signatures, and/or public key certificates used invalidating digital certificates.

Thus, the DigiBox may incorporate the information described above aspart of the control message, including the rules, the stream ID and thecryptographic keys and values.

In an alternative embodiment, DigiBox Header 1205 may be designed sothat it can be read by Demux 7 and routed to Control Block 13. In suchan embodiment, DigiBox 1204 would itself constitute the entirety of thecontrol message, thus obviating the need to nest DigiBox 1204 withinControl Message 1201.

Some or all of the contents of DigiBox 1204 will generally be encrypted.This may include Rules 1206, Data 1207, and possibly some or all ofHeader 1205. System 1 may be designed so that a DigiBox may only bedecrypted (opened) in a protected environment such as IRP 22. In analternate embodiment, Control Block 13 may directly incorporate thefunctionality of IRP 22, so that the DigiBox may be opened in ControlBlock 13 without the necessity of routing the DigiBox to IRP 22 forprocessing. In one embodiment, the cryptographic key used to decryptDigiBox 1204 may be stored in IRP 22 (or Control Block 13), so that theDigiBox can only be opened in that protected environment.

Rules 1206 are rules governing access to or use of DigiBox Data 1207. Inone embodiment, these rules do not directly control the governedstreams. Since Cryptographic Key 1209 can only be accessed and usedthrough compliance with Rules 1206, however, Rules 1206 in factindirectly control the governed streams, since those streams can only bedecrypted through use of the key, which can only be obtained incompliance with the rules. In another embodiment, Data 1207 may includeadditional rules, which may be extracted from the DigiBox and stored ina table such as Array 717 of FIG. 7.

The rules governing access to or use of a DigiBox may accompany theDigiBox, (as shown in FIG. 12) or may be separately transmitted, inwhich event Rules 1206 would contain a pointer or reference to the rulesused to access Data 1207. Upon receipt of a DigiBox, Control Block 13may receive rules separately through Control Stream 6, or may requestand receive rules through Port 21.

Pipelined Implementation

One potential drawback to the system illustrated in FIG. 1 consists ofthe fact that the system introduces complexity and feedback into apipelined system designed to render content in real time. The renderingpipeline generally consists of Demux 7, Organization Block 8 and AVBlock 9, Composite Block 11 and Rendering Device 12. Because content isreceived in a streamed fashion, and must be rendered in real time,pipelined processing must occur in a highly efficient manner, undertight time constraints. A failure to process within the time availablemay mean that output to Rendering Device 12 may be interrupted, or thatincoming Bit Stream 2 may overflow available buffers, thereby causingthe loss of some portion of the incoming data.

An alternative embodiment of System 1 is designed to address theseproblems, although at a possible cost in the ability to use standardsystem components and a possible cost in overall system security. Thisalternative embodiment is illustrated in FIG. 11, which shows System1101.

System 1101 is similar to System 1 from FIG. 1 in many respects. Itreceives Bit Stream 1102, which consists of Organization Stream 1103,Audio Stream 1104, Video Stream 1105 and Control Stream 1106. Thesestreams are received by Demux 1107, which passes Organization Stream1103 to Organization Block and passes Audio Stream 1104 and Video Stream1105 to AV Block 1109. Organization Block 1108 and AV Block 1109 operatesimilarly to their counterparts in FIG. 1, and pass information toComposite Block 1110, which organizes the information into a coherentwhole and passes it to Rendering Device 1111. Streams sent toOrganization Block 1108 are decrypted and/or validated by Stream FlowController 1112, and streams sent to AV Block 1109 are decrypted and/orvalidated by Stream Flow Controller 1113.

System 1101 differs from System 1, however, in that control and feedbackare distributed, and integrated directly into the processing andrendering pipeline. System 1101 thus lacks a separate control block, andalso lacks a feedback path back from the Composite Block 1110.

In System 1101, control is exercised directly at Organization Block 1108and AV Block 1109. As in System 1, cryptographic keys are receivedthrough Control Stream 1106 (in an alternative embodiment, the keyscould be incorporated directly into header or other information inOrganization Stream 1103 or Audio/Video Streams 1104 and 1105). Thosekeys are included in a data format which includes information regardingthe stream type of the encrypted content and, if multiple stream typesare possible, an identifier for the particular controlled stream.

When Demux 1107 encounters a key in Control Stream 1106, it reads theinformation relating to the stream type, and routes the key to theappropriate stream flow controller. If Demux 1107 encounters a keydesignated for decryption or validation of Organization Stream 1103, forexample, it routes that key to Stream Flow Controller 1112.

Stream Flow Controller 1112 stores received keys in Storage Location1114. Storage Location 1114 stores the keys and also stores an indicatorof the controlled stream ID.

Stream Flow-Controller 1112 includes Cryptographic Engine 1115, whichuses the received keys to decrypt and/or validate encrypted and/orprotected portions of Organization Stream 1103. The keys may themselvesbe received in an encrypted manner, in order to provide some degree ofsecurity. In such a case, Stream Flow Controller may use a variety oftechniques to decrypt the key, including using stored information as akey, or as a key seed. That stored information could, for example,constitute a “meta-key” provided earlier through Bit Stream 1102 orthrough a separate port.

Stream Flow Controller 1113, associated with AV Block 1109, contains acorresponding Storage Location 1116 and Cryptographic Engine 1117, andoperates in a manner similar to the operation described for Stream FlowController 1112.

This implementation avoids the latency penalty which may be inherent inthe necessity for communication between stream flow controllers and aseparate control block.

This alternate implementation may also eliminate the feedback channelfrom the composite block (FIG. 1, Control Line 16). This feedbackchannel may be used in order to insure that the content being passedfrom Composite Block 11 to Rendering Device 12 is content that has beenauthorized for rendering. In the alternate embodiment shown in FIG. 11,this feedback channel does not exist. Instead, this implementationrelies on the fact that Composite Block 1110 depends upon informationfrom Organization Block 1108 to determine the exact structure of theinformation being sent to Rendering Device 1111. Composite Block 1110cannot composite information in a manner contrary to the organizationdictated by Organization Block 1108.

In one embodiment, this control by Organization Block 1108 may besufficient to obviate the need for any feedback, since OrganizationBlock 1108 may be designed so that it accepts information only throughStream Controller 1112, and Stream Controller 1112 may be designed sothat it only decrypts or validates information under the control ofrules stored in Storage Location 1114.

In such an embodiment, security may be further increased byincorporating Secure Memory 1118 into Organization Block 1108. SecureMemory 1118 may store a copy or hash of the organization tree validlydecrypted by Stream Controller 1112, and in current use in MainOrganization Block Memory 1119. Organization Block 1108 may be used toperiodically compare the organization tree stored in Main OrganizationBlock Memory 1119 to the tree stored in Secure Memory 1118. If adiscrepancy is spotted, this may indicate that an attacker has alteredthe organization tree stored in Main Organization Block 1119, therebypossibly allowing for the rendering of content in violation ofapplicable rules. Under such circumstances, Organization Block 1108 maybe used to take protective measures, including replacing the contents ofMain Organization Block Memory 1119 with the contents of Secure Memory1118.

MPEG-4 Implementation

The generic system described above may be embodied in an MPEG-4 system,as illustrated in FIG. 8, which shows MPEG-4 System 801.

MPEG-4 System 801 accepts MPEG-4 Bit Stream 802 as input. MPEG-4 BitStream 802 includes BIFS Stream 803, OD Stream 804, Audio Stream 805,Video Stream 806 and IPMP Stream 807. These streams are passed to Demux808, which examines header information and routes packets asappropriate, to BIFS 809, AVO 810, OD 811 or IPMP System 812.

IPMP System 812 receives IPMP messages through IPMP Stream 807. Thosemessages may include header information identifying the particularmessage, as well as an associated IPMP message. The IPMP message mayinclude control information, which may include a cryptographic key,validation information, and/or may include complex governance rules, asare described above.

Stream Controllers 813, 814 and 815 act to decrypt, validate, and/orgovern streams passed to BIFS 809, AVO 810 and OD 811, respectively.

OD 811 holds object descriptors, which contain metadata describingparticular objects. This metadata includes an identifier of theparticular Elementary Stream or streams which include the object, andmay also include a pointer to a particular IPMP message which governsthe object. Alternatively, the relationship between IPMP messages andparticular objects or streams may be stored in a table or other formwithin IPMP System 812.

IPMP System 812 may exercise control over other functional blocksthrough Control Lines 816, 817, 818 and 819, each of which may transmitcontrol/governance signals from IPMP System 812 and information orrequests from other functional blocks to IPMP System 812. Theinformation requests may include an ES_ID and a time stamp, which IPMPSystem 812 may use to determine which particular message (e.g., key)should be used and when.

In an alternative embodiment, IPMP System 812 may exercise control overComposite and Render 821 by receiving a hash of the currently valid BIFStree (possibly through IPMP stream 807), and periodically checking thehash against the BIFS tree stored in BIFS 809. Because BIFS 809 controlsthe manner in which Composite and Render 821 renders information, ifIPMP System 812 confirms that the current BIFS tree is the same as theauthorized tree received through BIFS Stream 803, IPMP System 812 canconfirm that the proper content is being rendered, even withoutreceiving feedback directly from Composite and Render 821. This may benecessary, since BIFS 809 may communicate with Port 822, which may allowa user to insert information into BIFS 809, thereby creating apossibility that a user could insert an unauthorized BIFS tree andthereby gain unauthorized access to content.

When a stream controller receives encrypted or otherwise governedinformation, it may send the ES_ID and time stamp directly to IPMPSystem 812. Alternatively, it may send this information to OD 811, whichmay reply with the ID of the IPMP message which governs that object orstream. The stream controller can then use that IPMP message ID torequest decryption, validation, and/or governance from IPMP System 812.Alternatively, OD 811 can pass the IPMP ID to IPMP System 812, which caninitiate contact with the appropriate stream controller.

IPMP System 812 may obtain IPMP information through two channels otherthan IPMP Stream 807. The first of these channels is Port 820, which maybe directly connected to a device or memory (e.g., a smart card, a DVDdisk, etc.) or to an external network (e.g., the Internet). An IPMPmessage may contain a pointer to information obtainable through Port812, such as a URL, address on a DVD disk, etc. That URL may containspecific controls needed by the IPMP message, or may contain ancillaryrequired information, such as, for example, information relating to thebudget of a particular user.

IPMP System 812 may also obtain IPMP information through OD updatescontained in OD Stream 804. OD Stream 804 contains metadata identifyingparticular objects. A particular OD Message may take the format shown inFIG. 9. In this figure, OD Message 901 includes Header 902, whichidentifies the following packets as part of the OD stream, and indicatesthe number of packets. OD Message 901 further consists of Message 903,which includes a series of Pointers 904 and associated Metadata 905.Each Pointer 904 identifies a particular Elementary Stream, and theassociated metadata is applicable to that stream. Finally, OD Message901 may contain an IPMP Pointer 906, which identifies a particular IPMPmessage.

In aggregate, the information contained in OD Message 901 constitutes anobject descriptor, since it identifies and describes each elementarystream which makes up the object, and identifies the IPMP message whichgoverns the object. OD Message 901 may be stored in OD 811, along withother messages, each constituting an object descriptor.

Object descriptors stored in OD 811 may be updated through OD Stream804, which may pass through a new object descriptor corresponding to thesame object. The new object descriptor then overwrites the existingobject descriptor. This mechanism may be used to change the IPMP messagewhich controls a particular object, by using a new object descriptorwhich is identical to the existing object descriptor, with the exceptionof the IPMP pointer.

OD Stream 804 can also carry IPMP_DescriptorUpdate messages. Each suchmessage may have the same format as IPMP messages carried on the IPMPstream, including an IPMP ID and an IPMP message.

IPMP_DescriptorUpdate messages may be stored in a table or array in OD811, or may be passed to IPMP System 812, where they may overwriteexisting stored IPMP messages, or may add to the stored messages.

Since IPMP information may be separately conveyed through the OD streamor the IPMP stream, MPEG-4 System 801 may be designed so that it onlyaccepts information through one or the other of these channels.

In another embodiment, the existence of the two channels may be used toallow multi-stage distribution, with governance added at later stages,but with no risk that later alterations may override governance added atan earlier stage.

Such a system is illustrated in FIG. 10. In this Figure, IPMP System 812includes IPMP Table 1002, which has slots for 256 IPMP messages. Thistable stores the IPMP_ID implicitly, as the location at which theinformation is stored, shown in Column 1003. The IPMP message associatedwith IPMP_ID 4, for example, is stored at slot 4 of IPMP Table 1002.

Each location in IPMP Table 1002 includes Valid Indicator 1004 andSource Indicator 1005. Valid Indicator 1004 is set for a particularlocation when an IPMP message is stored at that location. This allowsIPMP System 812 to identify slots which are unfilled, which otherwisemight be difficult, since at start-up the slots may be filled withrandom information. This also allows IPMP System 812 to identifymessages which are no longer valid and which may be replaced. ValidIndicator 1004 may store time stamp information for the period duringwhich the message is valid with IPMP System 812 determining validity bychecking the stored time stamp information against the currently validtime.

Source Indicator 1005 is set based on whether the associated IPMPmessage was received from IPMP Stream 807 or from OD Stream 804.

These indicators allow IPMP System 812 to establish a hierarchy ofmessages, and to control the manner in which messages are added andupdated. IPMP System 812 may be designed to evaluate the indicators fora particular location once a message is received corresponding to thatlocation. If the valid indicator is set to invalid, IPMP System 812 maybe designed to automatically write the IPMP message into that slot. Ifthe valid indicator is set to valid, IPMP System 812 may then bedesigned to check the source indicator. If the source indicatorindicates that the associated message was received through OD Stream804, IPMP System 1812 may be designed to overwrite the existing messagewith the new message. If, however, the source indicator indicates thatthe associated message was received through IPMP Stream 807, IPMP System812 may be designed to check the source of the new message. That checkmay be accomplished by examining the header associated With the newmessage, to determine if the new message was part of OD Stream 804 orpart of IPMP Stream 807. Alternatively, IPMP System 812 may derive thisinformation by determining whether the message was received directlyfrom Demux 808 or through OD 811.

If the new message came through IPMP Stream 807, IPMP System 812 may bedesigned to store the new message in Table 1002, overwriting theexisting message. If the new message came through OD Stream 804, on theother hand, IPMP System 812 may be designed to reject the new message.

This message hierarchy can be used to allow for a hierarchy of control.A studio, for example, may encode a movie in MPEG-4 format. The studiomay store IPMP messages in the IPMP stream. Those messages may include arequirement that IPMP System 812 require that a trailer for anothermovie from the same studio be displayed prior to the display of thefeature movie. IPMP System 812 could be used to monitor the beginningand end of rendering of the trailer (using feedback through Control Line819) to ensure that the entire trailer plays, and that the user does notfast-forward through it.

The movie studio could encrypt the various elementary streams, includingthe IPMP stream. The movie studio could then provide the movie to adistributor, such as a cable channel. The movie studio could provide thedistributor with a key enabling the distributor to decrypt the OD stream(or could leave the OD stream unencrypted), and the ability to insertnew messages in that stream. The cable channel could, for example,include a rule in the OD stream specifying that the IPMP system check todetermine if a user has paid for premium viewing, decrypt the movie ifpremium viewing has been paid for, but insert advertisements (andrequire that they be rendered) if premium viewing has not been paidfor).

The cable channel would therefore have the ability to add its own rulesinto the MPEG-4 Bit Stream, but with no risk that the cable channelwould eliminate or alter the rules used by the movie studio (e.g., bychanging the trailer from a movie being promoted by the studio to arival movie being promoted by the cable channel). The studio's rulescould specify the types of new rules which would be allowed through theOD stream, thereby providing the studio a high degree of control.

This same mechanism could be used to allow superdistribution of content,possibly from one user to another. A user could be provided with aprogramming interface enabling the insertion of messages into the ODstream. A user might, for example, insert a message requiring that apayment of $1.00 be made to the user's account before the movie can beviewed. The user could then provide the movie to another user (ordistribute it through a medium whereby copying is uncontrolled, such asthe Internet), and still receive payment. Because the user's rules couldnot overrule the studio's rules, however, the studio could be certainthat its rules would be observed. Those might include rules specifyingthe types of rules a user would be allowed to add (e.g., limiting theprice for redistribution).

MPEG-4 System 801 may also be designed to include a particular type ofIPMP system, which may be incompatible with IPMP systems that may bedesigned into other MPEG-4 systems. This may be possible because theMPEG-4 standard does not specify the format of the information containedin the IPMP stream, thereby allowing different content providers toencode information in differing manners.

IPMP System 812 in MPEG-4 System 801 may be designed for an environmentin which differing IPMP formats exist. That system may scan the IPMPstream for headers that are compatible with IPMP System 812. All otherheaders (and associated packets) may be discarded. Such a mechanismwould allow content providers to incorporate the same IPMP message inmultiple formats, without any concern that encountering an unfamiliarformat would cause an IPMP system to fail. In particular, IPMP headerscan incorporate an IPMP System Type Identifier. Those identifiers couldbe assigned by a central authority, to avoid the possibility that twoincompatible systems might choose the same identifier.

IPMP System 801 might be designed to be compatible with multipleformats. In such a case, IPMP System 801 might scan headers to locatethe first header containing an IPMP System Identifier compatible withIPMP System 801. IPMP System 801 could then select only headerscorresponding to that IPMP System Identifier, discarding all otherheaders, including headers incorporating alternate IPMP SystemIdentifiers also recognized by the IPMP system.

Such a design would allow a content provider to provide multipleformats, and to order them from most to least preferred, by includingthe most preferred format first, the second most preferred formatsecond, and so on. Since IPMP System 801 locks onto the first compatibleformat it finds, this ordering in IPMP Stream 801 would insure that theIPMP system chose the format most desired by the content provider.

Even if different IPMP formats are used, content will probably beencoded (and encrypted) using a single algorithm, since sending multipleversions of content would impose a significant bandwidth burden. Thus,ordinarily it will be necessary for content to be encrypted using arecognized and common encryption scheme. One such scheme could use theDES algorithm in output feedback mode.

This method of screening IPMP headers, and locking onto a particularformat may also be used to customize an MPEG-4 bit Stream for thefunctional capabilities of a particular MPEG-4 system. Systems capableof rendering MPEG-4 content may span a considerable range offunctionality, from high-end home theaters to handheld devices.Governance options suitable for one type of system may be irrelevant toother systems.

For example, MPEG-4 System 801 may include a connection to the Internetthrough Port 820, whereas a second MPEG-4 system (for example a handheldWalkman-like device) may lack such a connection. A content providermight want to provide an option to a viewer, allowing the viewer to seecontent for free in return for providing information about the viewer.The content provider could insert a rule asking the user whether theuser wants to view the content at a cost, or enter identificationinformation. The rule could then send the information through a port tothe Internet, to a URL specified in the rule. A site at that URL couldthen evaluate the user information, and download advertisements targetedto the particular user.

Although this might be a valuable option for a content provider, itobviously makes no sense for a device which is not necessarily connectedto the Internet. It would make no sense to present this option to theuser of a non-connected device, since even if that user entered theinformation, the rule would have no way to provide the information to anexternal URL or download the advertisements. In such a case, the contentprovider might prefer to require that the user watch preselected adscontained in the original MPEG-4 bit stream.

Header information in the IPMP stream could be used to customize anMPEG-4 bit stream for particular devices. As with the IPMP System Typeinformation, IPMP Header information could include MPEG-4 System Types.These could include 8 or 16-bit values, with particular featuresrepresented by bit maps. Thus, the presence of a bit at position 2, forexample, could indicate that a device includes a persistent connectionto the Internet.

An IPMP system could then evaluate the headers, and lock on to the firstheader describing functionality less than or equal to the functionalitycontained in the MPEG-4 device in which the IPMP system is embedded. Ifthe header constituted a complete match for the functionality of theMPEG-4 device, the IPMP system could then cease looking. If the headerconstitutes less than a complete match (e.g., a header for a systemwhich has an Internet connection, but lacks a digital output port, whenthe system includes both), the IPMP system can lock on to that header,but continue to scan for closer matches, locking on to a closer match ifand when one is found.

The IPMP messages identified by a particular header would be thosesuited for the particular functionality of the MPEG-4 device, and wouldallow for customization of the MPEG-4 bit stream for that functionality.In the context of the example given above, the IPMP system for an MPEG-4device containing an Internet connection would lock on to a particularheader, and would download the IPMP messages characterized by thatheader. Those messages would prompt the user for information, wouldprovide that information to the URL, and would authorize decryption andrendering of the movie, with the advertisements inserted at theappropriate spot.

In the case of an MPEG-4 device without an Internet connection, on theother hand, the IPMP system would lock onto a set of headers lacking thebit indicating an Internet connection, and would download the rulesassociated with that header. Those rules might not provide any option tothe user. The rules might allow decryption of the content, but wouldalso specify decryption of an additional ES from the MPEG-4 stream. Thatadditional ES would contain the advertisements, and the IPMP systemwould require decryption and rendering of the advertisements, checkingControl Line 819 to make certain that this had occurred. In the case ofthe system with the Internet connection, however, the rules allowingdecryption and requiring rendering of the ES containing theadvertisements would never be loaded, since those rules would becontained within messages identified by the wrong type of header. Theadvertisement ES would therefore never be decrypted and would be ignoredby the MPEG-4 device.

FIG. 21 illustrates one manner in which a protected MPEG-4 file may becreated. In this figure, CreateBox 2101 represents a DigiBox creationutility, which accepts keys and rules. In one embodiment, CreateBox 2101may pass these keys and rules to IRP 2102 and receive DigiBox 2103 fromIRP 2102. In another embodiment, IRP 2102 may be incorporated intoCreateBox 2101, which accepts keys and rules and outputs DigiBox 2103.

DigiBox 2103 contains governance rules, initialization vectors and keys.DigiBox 2103 is passed from CreateBox 2101 to Bif Encoder 2104. BifEncoder 2104 may be conventional, with the exception that it is designedto accept and process DigiBoxes such as DigiBox 2103. Bif Encoder 2104also accepts a .txt file containing a scene graph, and initial objectdescriptor commands.

Bif Encoder 2104 outputs a .bif file, containing the scene graph stream(in compressed binary form) and a .od file, containing the initialobject descriptor commands, the object descriptor stream, and DigiBox2103.

Bif Encoder 2104 passes the .bif file and the .od file to Mux 2105. Mux2105 also accepts compressed audio and video files, as well as a .scrfile that contains the stream description. Mux 2105 creates IPMPstreams, descriptors and messages, encrypts the content streams,interleaves the received streams, and outputs Protected MPEG-4 ContentFile 2106, consisting of Initial Object Descriptor 2107 and EncryptedContent 2108. Initial Object Descriptor 2107 contains DigiBox 2103, aswell as other information. Encrypted Content 2108 may include a scenegraph stream (i.e., a BIFS stream), an object descriptor stream, IPMPstreams, and encrypted content streams.

If DigiBox 2103 contains all keys and rules necessary to render all ofthe content, it may be unnecessary for Mux 2105 to create any IPMPstreams. If additional keys or rules may be necessary for at least aportion of the content, Mux 2105 may incorporate those rules and keysinto one or more additional DigiBoxes, and incorporate those DigiBoxeseither in the IPMP stream or in the OD update stream.

FIG. 22 illustrates one manner in which control may be incorporated intoan existing MPEG-4 stream. In this figure, Unprotected MPEG-4 ContentFile 2201 includes Initial Object Descriptor 2202 and Content 2203. Thecontent may include a scene description stream (or BIF stream), anobject descriptor stream, a video stream, an audio stream, and possiblyadditional content streams.

Unprotected MPEG-4 Content File 2201 is passed to Repackager 2204, whichalso accepts keys and rules. Repackager 2204 passes the keys and rulesto IRP 2205, and receives DigiBox 2206 in return, containing keys, rulesand initialization vectors. In an alternate embodiment, IRP 2205 may beincorporated directly into Repackager 2204.

Repackager 2204 demuxes Unprotected MPEG-4 Content File 2201. It insertsDigiBox 2206 into the Initial Object Descriptor and encrypts the variouscontent streams. Repackager 2204 also adds the IPMP stream, if this isnecessary (including if additional DigiBoxes are necessary).

Repackager 2204 outputs Protected MPEG-4 Content File 2207, consistingof Initial Object Descriptor 2208 (including DigiBox 2206) and EncryptedContent 2209 (consisting of various streams, including the IPMP streams,if necessary).

Real Networks Implementation

In one embodiment, the elements described above may be used inconnection with information encoded in compliance with formatsestablished by Real Networks, Inc.

The Real Networks file format (RMFF) is illustrated in FIG. 13. Thisformat includes a block of headers at the beginning (Header 1301),followed by a collection of content packets (Content 1302), followed byan index used for seek and goto operations (Index 1303). Each file cancontain several streams of different types. For each stream, there is a“Media Properties Header” (1304) used to describe the format of themedia content (e.g., compression format) and provide stream specificinformation (e.g., parameters for the decompressor).

Real Networks streams can be protected by inserting a DigiBox intoHeader 1301 and encrypting the data packets contained in Content 1302.The altered format is illustrated in FIG. 14, which shows Header 1401,including Media Properties Headers 1402 and 1403, which in turn containDigiBoxes 1404 and 1405, respectively. The format also includesencrypted Content 1406 and Index 1407.

In one embodiment, the declared type of the data is changed from thestandard Real Networks format to a new type (e.g., RNWK_Protected.) Theold type is then saved. Changing the type forces the Real Networksplayer to load a “Trust Plugin,” since this Plugin is registered as theonly decoder module that can process streams of type “RNWK-Protected.”The Trust Plugin opens the DigiBox, gets approval from the user, if itis needed, determines the original content type, loads a decoder pluginfor the original content, and then decrypts and/or validates thecontent, passing it to the content decoder plugin to be decompressed andpresented to the user.

In one embodiment, the specific alterations made to the Real Networksfile format are the following:

-   -   Increase the preroll time to force larger buffers on playback.        In a current embodiment, an increase of 3 seconds is used.        Larger buffers are needed because of the extra steps needed to        decrypt the content.    -   Modify each stream-specific header by changing the mime type to        “RNWK-Protected”, saving the old mime type in the decoder        specific information and adding a content identifier and DigiBox        to the decoder specific information. The DigiBox contains the        key, initialization vector (IV), version information, and        watermarking instructions. The key, IV and content identifier        are generated automatically, or can be provided as command-line        parameters. The same key, IV and content identifier are used for        every stream.    -   Content packets are selectively encrypted. In one embodiment,        content packets whose start time in milliseconds is in the first        half-second of each 5 seconds (i.e., starttime % 5000<500) are        encrypted. This encrypts approximately one-tenth of the content        reducing encryption and decryption costs, and damages the        content, sufficiently to prevent resale. The encryption        algorithm can be DES using output-feedback mode or any similar        algorithm. The initialization vector is computed for each packet        by xoring the stream's IV with the packet's start time in        milliseconds. Some information unique to the stream should also        be xored into the IV. In one embodiment, the same IV is used for        multiple packets whenever two or more streams have packets with        the same start time. This usually happens for the first packet        in each stream since they usually have start time 0. Other than        the first packet, it is rare to have two packets have the same        start time.

In one embodiment, these changes to the Real Networks file format areaccomplished as is shown in FIG. 15. As is illustrated, RMFF file 1501is formatted in the standard Real Networks RMFF format. This file ispassed to Packager 1502. Also passed to Packager 1502 is Rights File1503. Packager 1503 generates Protected RMFF File 1504, which includesvarious alterations as described above and as listed in FIG. 15,including the incorporation of one or more DigiBoxes in the header,encryption of the content, modification of the mime type, etc.

In one embodiment, the trust plugin described above is illustrated inFIGS. 16 and 17. FIG. 16 illustrates the standard Real Networksarchitecture. File 1601 (e.g., a streaming audio file in Real Networksformat) is provided to Real Networks G2 Client Core 1602. File 1601 maybe provided to Real Networks G2 Client Core 1602 from Server 1603, orthrough Direct Connection 1604.

Upon receipt of File 1601, Real Networks G2 Client Core 1602 accesses arendering plugin appropriate to File 1601, based on information which isobtained from the header associated with File 1601. Rendering Plugins1605 and 1606 are shown. If File 1601 is of a type which cannot berendered by either Rendering Plugin 1605 or Rendering Plugin 1606, RealNetworks G2 Client Core 1602 may attempt to access an appropriateplugin, e.g., by asking for the user's assistance or by accessing a siteassociated with the particular file type.

Rendering Plug-In 1605 or 1606 processes File 1601 in a conventionalmanner. This processing most likely includes decompression of File 1601,and may include other types of processing useful for rendering thecontent. Once this processing is complete (keeping in mind that thecontent is streamed, so that processing may be occurring on one set ofpackets at the same time that another set of packets is being rendered),File 1601 is passed back to Real Networks G2 Client Core 1602, whichthen passes the information to Rendering Device 1607. Rendering Device1607 may, for example, be a set of stereo speakers, a televisionreceiver, etc.

FIG. 17 illustrates the manner in which a trust plugin operates withinthe overall Real Networks architecture. Much of the architectureillustrated in FIG. 17 is the same as that illustrated in FIG. 16. Thus,File 1701 is provided to Real Networks G2 Client Core 1702 throughServer 1703 or through Direct Connection 1704. The file is processed byReal Networks G2 Client Core 1702, using plugins, including RenderingPlugins 1705 and 1706, and is then passed to Rendering Device 1707.

FIG. 17 differs from FIG. 16 in its incorporation of Trust Plugins 1708and 1709, and IRP 1710. When initially registered with Real Networks G2Client Core 1702, Trust Plugins 1708 and 1709 inform Real Networks G2Client Core 1702 that they can process content of type RNWK-Protected.Whenever Real Networks G2 Client Core 1702 encounters a stream of thistype, it is then enabled to create an instance of the trust plugin toprocess the stream, e.g., Trust Plugin 1708. It then passes the streamto the trust plugin.

The stream passed to Trust Plugin 1708 may be in the format shown inFIG. 14. In such a case, Trust Plugin 1708 extracts DigiBox 1404 fromMedia Properties Header 1402. It also extracts the content id andoriginal mime type from Media Properties Header 1402. The Trust Pluginfirst checks to see if any other stream with the same content identifierhas been opened. If so, then DigiBox 1404 is not processed further.Instead, the key and IV from the box for this other stream are used.This avoids the time cost of opening a second box. Also, this ensuresthat a user is only asked to pay once even if there are multipleprotected streams. By sharing content ids, keys, and IVs, several filescan be played with the user only paying once. This is useful when SMILis used to play several RMFF files as a single presentation.

In an alternate and possibly more secure embodiment, this check is notperformed, and the key and IV from the current DigiBox are used even ifanother stream with the content identifier has already been opened.

If no other stream has been identified with the same content identifier,Trust Plugin 1708 passes DigiBox 1404 to IRP 1710. IRP 1710 may be asoftware process running on the same computer as Real Networks G2 ClientCore and Trust Plugin 1708. IRP 1710 may run in a protected environmentor may incorporate tamper resistance techniques designed to render IRP1710 resistant to attack.

IRP 1708 may process DigiBox 1404 and extract a cryptographic key and anIV, which may then be passed to Trust Plugin 1708. Trust Plugin 1708 maythen use this information to decrypt Encrypted Contents 1406.

Trust Plugin 1708 uses the original mime type information extracted fromMedia Properties Header 1402 to create an instance of the renderingplugin to be used for the content (e.g., Rendering Plugin 1705). Oncethis is done, Trust Plugin 1708 behaves like an ordinary renderingplugin to the Real Networks G2 Client Core 1702, in that Real NetworksG2 Client Core 1702 passes streamed information to Trust Plugin 1708,which decrypts that information and passes it to Rendering Plugin 1705.From the perspective of Real Networks G2 Client Core 1702, Trust Plugin1708 constitutes the appropriate rendering pluin, and the core is notaware that the information is being passed by Trust Plugin 1708 to asecond plugin (e.g., Rendering Plugin 1705).

Similarly, from the point of view of Rendering Plugin 1705, Trust Plugin1708 behaves like Real Networks G2 Client Core 1702. Thus althoughRendering Plugin 1705 receives decrypted stream information from TrustPlugin 1708, Rendering Plugin 1705 operates exactly as if theinformation had been received directly from Real Networks G2 Client Core1702. In this manner, content formatted for Rendering Plugin 1705 mayinstead be first processed by Trust Plugin 1708, without requiring anyalteration to Real Networks G2 Client Core 1702 or Rendering Plugin1705.

Trust Plugin 1708 may also perform other processing that may be helpfulfor security purposes. For example, Trust Plugin 1708 may watermark thedecrypted file prior to passing it to Rendering Plugin 1705, keeping inmind that the watermark algorithm must be such that it will survivedecompression of the file by Rendering Plugin 1705.

MP3 Embodiment

The techniques described above can also be applied to MP3 streamingcontent.

The MP-3 specification does not define a standard file format, but doesdefine a bit stream, which is illustrated in FIG. 18. In FIG. 18, MP-3Bit Stream 1801 includes Content 1802. Content 1802 is divided intoframes, shown as Frame 1803, Frame 1804 and Frame 1805. The dots betweenFrame 1804 and 1805 symbolize the fact that Content 1802 may include alarge number of frames.

Each frame includes its own small header, shown in FIG. 18 as Headers1806, 1807 and 1808.

Many MP3 players support a small trailer defined by the ID3 V1specification, shown as Trailer 1809. This is a 128 byte trailer forcarrying fields like artist, title and year, shown as Fields 1810, 1811and 1812. The ID3 V1 trailer is ignored by players not designed to readsuch trailers, since it does not appear to be valid MP3 data.

FIG. 19 shows one embodiment of protection applied to the MP3 format.This protected format constitutes File 1908 and includes the followingitems:

-   -   Unencrypted MP3 Content 1912. This is the first information        encountered by a player, and will be rendered by any standard        MP3 player. It can include a message to the user indicating that        the content is protected and providing instructions as to how        the content can be accessed (e.g., a URL for a trust plugin,        instructions on payment mechanisms, etc.) Unencrypted MP3        Content 1912 may include a “teaser,” consisting of an initial        portion of the content (e.g., 30 seconds), which is rendered at        no cost, thereby allowing a user to sample the content prior to        making a decision to purchase it.    -   Encrypted MP-3 Content 1901, which may include thousands of MP-3        frames. In one embodiment, the first eight frames out of every        32 frames are encrypted. Thus, one-quareter of the frames are        rendered unuseable unless a player is able to decrypt them. In        practice, this may render the content un-sellable or unuseable,        without imposing excessive encryption or decryption costs. To        further reduce encryption and decryption costs, only 32 bytes in        each frame are encrypted. In a current embodiment, these are the        first 32 bytes after the header and CRC information. In a        different embodiment, a different 32 bytes may be encrypted in        every frame. In a current embodiment, the content is encrypted        with the DES using algorithm output-feedback mode. The initial        IV for the file is randomly generated and then xored with the        frame number to generate a unique IV for each frame.

Many alternate embodiments may exist, including encypting more or lessinformation, and using different encryption algorithms.

-   -   ID3 V1 Trailer 1902, including 128 bytes.    -   Content ID 1903, including 16 bytes. This is used by the player        application to avoid opening DigiBoxes which it has already        opened.    -   DigiBox 1904, which may comprise approximately 18 K bytes. It        includes Key 1909, IV 1910 and Watermarking Instructions 1911.        Watermarking Instructions 1911 may be used in a process of        watermarking the associated content.    -   Address 1905, which contains the address in the file of Content        ID 1903 and consists of 4 bytes.    -   Trust ID 1906, which identifies this trusted MP-3 file and        consists of 16 bytes.    -   ID3 V1 Trailer 1907, which is a copy of Trailer 1902.

A conventional MP3 player encountering File 1908 would be unable torender Content 1901, since at least a portion of that content isencrypted. Such a player would most likely read through to Trailer 1902and cease processing at that point. A conventional player looking forthe ID3 trailer information will seek to the end and find it.

FIG. 20 illustrates one embodiment of an MP3 player designed to processand render protected content. This figure shows MP3 Player 2001, whichincludes Buffer 2006 and Decompressor 2007, and renders content toRendering Device 2008. In one embodiment, this is a modified version ofa player distributed by Sonique.

Player 2001 obtains Protected MP3 File 2002 through any standardinterface. Protected MP3 File 2002 may have the format illustrated inFIG. 19.

When Player 2001 is asked to play Protected MP3 File 2002, Player 2001first calls Trust Plug-In 2003, which includes Approval Function 2009and Decrypt Function 2005. Trust Plugin 2003 calls Approval Function2009 to determine if Protected MP3 File 2002 is protected and whetherauthorization exists to play the file. Approval Function 2009 is firstgiven a pointer to Protected MP3 File 2002. It then checks Protected MP3File 2002 for the presence of Trust ID 1906. If Trust ID 1906 is notfound, Approval Function 2009 returns an indicator that the file is notprotected. Player 2001 then proceeds to render the file as a normal MP3file.

If Trust ID 1906 is found, Approval Function 2009 checks Content ID 1903to see if it matches the Content ID of a file that has already beenopened.

If Protected MP3 File 2002 has not been previously opened, DigiBox 1904is retrieved by Approval Function 2009, and is passed to IRP 2004, whichmay include software running in a protected environment, orincorporating tamper resistance. IRP 2004 attempts to open DigiBox 1904in compliance with the rules associated with that DigiBox. One such rulemay require, for example, that the user indicate assent to pay for useof the content. If DigiBox 1904 cannot be opened (e.g., the user refusesto pay) a value is returned to Approval Function 2009 indicating thatthe file is protected and may not be played.

If DigiBox 1904 is opened in compliance with applicable rules, the keyand IV are retrieved and passed to Decrypt Function 2005. The key and IVare stored with the content id for later re-use and Decrypt Function2005 is initialized. This may improve overall system performance, sinceit reduces the number of times a DigiBox must be opened. Each suchaction may introduce significant latency.

On the other hand, storing this information in unprotected memory mayreduce overall system security. Security may be enhanced either by notstoring this information (thereby requiring that each DigiBox be opened,even if the corresponding file has already been opened through anotherDigiBox), or by storing this information in a protected form or in asecure location.

The stored key, IV and content id are referenced when Approval Function2009 first checks Content ID 1903 to determine if it matches the ContentID of an already opened file. If the new Content ID matches a storedContent ID, Decrypt Function 2005 is reinitialized using the stored keyand IV corresponding to the matching content id and a value indicatingthat this is a protected file for which play is authorized is returnedto Approval Function 2009.

Once Protected MP3 File 2002 has been opened, each time Player 2001needs a packet, Player 2001 reads it into Buffer 2006, strips off theheader and CRC and passes the remaining data and a frame number toDecrypt Function 2005, which decrypts the frame if necessary, andreturns it to Player 2001.

In a current embodiment, although audio content is encrypted, headers ortrailers are not encrypted. This allows the Player 2001 to processinformation in headers or trailers without intervention from ApprovalFunction 2009 or Decrypt Function 2005. This allows Player 2001 to placeinformation such as playing time, artist and title into a playlistdisplay, and initialize Decompressor 2007, without any action requiredfrom Trust Plugin 2003.

Commerce Appliance Embodiment

This section will describe an embodiment, comprising a CommerceAppliance architecture designed to allow persistent control of digitalworks in consumer electronics devices. Although this is described as aseparate embodiment, it should be understood that the features of thisembodiment may be combined with, or supplant, the features of any of theembodiments provided elsewhere in this description.

In one embodiment, this section will describe modifications to theMPEG-4 standard designed to support the association of persistent rulesand controls with MPEG-4 content, as well as elements necessary for aCommerce Appliance to use such content. This is intended, however,merely as an example.

In one embodiment, shown in FIG. 23, each Commerce Appliance 2301includes a CMPS (“Content Management and Protection System”) 2302. EachCMPS is responsible for governing the use of controlled content,including decrypting the content and ensuring that the content is onlyused as permitted by associated rules.

Each governed digital work is associated with one or more CMPOs (ContentManagement Protection Object), e.g., CMPOs 2303. Each CMPO may specifyrules governing the use of the digital work, and may include keys usedto decrypt the work.

CMPOs may be organized in an hierarchical fashion. In one embodiment, acontent aggregator (e.g., a cable channel, a web site, etc.) may specifya Channel CMPO (“CCMPO”) used to associate certain global rules with allcontent present on that channel. Each independent work may in turn havean associated Master CMPO (“MCMPO”) used to associate rules applicableto the work as a whole. Each object (or Elementary Stream, in MPEG-4)may have associated with it a CMPO containing rules governing theparticular object.

In one exemplary application, Commerce Appliance 2301 may be an MPEG-4player containing CMPS 2302. Upon receipt of a user command to play aparticular work, CMPS 2302 may download a MCMPO associated with the workand obtain rules, which may include conditions required for decryptionand viewing of the work. If the rules are satisfied, CMPS 2302 may usekeys from the MCMPO to decrypt any Elementary Streams (“ES”), and maypass the decrypted ESs into the buffers. Composition and rendering ofthe MPEG-4 work may thereafter proceeds according to the MPEG-4standard, except that any storage location or bus which may contain thework in the clear must be secure, and CMPS 2302 may have the ability togovern downstream processing, as well as to obtain information regardingwhich AVOs were actually released for viewing.

In a variation, the process of obtaining and governing the work mayinclude downloading a CCMPO which applies rules governing this and otherworks. If rules contained in the CCMPO are satisfied, CMPS 2302 mayobtain a key used to decrypt the MCMPO associated with the particularwork to be viewed.

In another variation, a CMPO may be associated with each ES. In thisvariation, the MCMPO supplies one or more keys for decryption of eachCMPO, and each CMPO may in turn supply a key for decryption of theassociated ES.

Commerce Appliance 2301 is a content-rendering device which includes thecapability of supporting distributed, peer management of content relatedrights by securely applying rules and controls to govern the use ofcontent. Commerce Appliance 2301 may include general-purpose functionsdevoted to acquisition and managed rendering of content (e.g., a DVD(and/or any other optical disk format) player is able to play a DVD(and/or any other optical disk format) disk and output content to atelevision.) Commerce Appliance 2301 may make use of any of the meansfor protecting and using digital content on high capacity optical disk,in one non-limiting example, a DVD disk, as described in theaforementioned Shear patent application.

Commerce Appliance 2301 also includes special-purpose functions relatingto other management and protection of content functions. Thesespecial-purpose functions may be supported by one or more embedded orotherwise included CMPS 2302 in the form of a single CMPS or acooperative CMPS arrangement, and may include a user interface (e.g.,User Interface 2304) designed to display control-related information tothe user and/or to receive control-related information and directionsfrom the user. Commerce Appliance 2301 may also be designed so that itis networkable with other Commerce Appliances (e.g., a set-top boxconnected to a DVD player and a digital television) and/or with otherdevices, such as a computer arrangement, which may also include one ormore CMPSs.

An important form of Commerce Appliance specifically anticipates securecoupling on a periodic or continual fashion with a computer manageddocking environment (e.g., a standalone computer or other computermanaged device which itself may be a Commerce Appliance) where the oneor more CMPSs of the Commerce Appliance interoperate with the dockingenvironment to form a single user arrangement whose performance ofcertain functions and/or certain content usage events is enabled by suchinter-operation through, at least in part, cooperation between CMPSs andcontent usage management information of the Commerce Appliance and thetrust environment capabilities of the docking environment, (e.g.,further one or more CMPSs and content usage management information, suchas, for example, information provided by use of CI).

An exemplary Commerce Appliance may be designed to comply with theemerging MPEG-4 standard for the formatting, multiplexing, transmission,compositing, and rendering of video and other types of information.

Commerce Appliance 2301 may be any computing device, one non-limitingexample of which is a Personal Computer (PC) that includes MPEG-4software (and/or hardware) for rendering content. In accordance with thepresent invention, the PC may also use one or more CMPSs as describedherein.

The commerce appliance function is not restricted to streamed channelcontent but may include various browser-type applications consisting ofaggregated composite content such as still imagery, text, synthetic andnatural video and audio and functional content such as applets,animation models and so on, these devices include browsers, set-topboxes, etc.

Content Management and Protection System (CMPS)

Each commerce appliance includes one or more CMPS (e.g., CMPS 2302). TheCMPS is responsible for invocation and application of rules andcontrols, including the use of rules and controls to govern the mannerin which controlled content is used.

Particular functions of CMPS 2302 include the following:

-   -   (a) Identification and interpretation of rules.

CMPS 2302 must determine which rules are to be applied, and mustdetermine how those rules are to be interpreted in light of existingstate information. In one embodiment, this requires that CMPS 2302obtain and decrypt one or more CMPOs 2303 associated with a work.

-   -   (b) Identification of content associated with particular rules.

CMPS 2302 must determine which content is governed by particular one ormore rules. This may be accomplished by obtaining information from oneor more CMPOs 2303 and/or other CI. In one embodiment, a CCMPO mayidentify a set of works, a MCMPO may identify a particular work and aCMPO may identify a particular ES or Audio Visual Object (“AVO”).

-   -   (c) Decryption of content as allowed by the rules.

CMPS 2302 may be designed so that all content is routed through CMPS2302 for decryption, prior to reinsertion into the data flow required bythe relevant standard. In the case of MPEG-4, for example, the outputfrom Demux 2305 may be fed into CMPS 2302. CMPS 2302 may then decryptthe content and, if relevant rules and controls are satisfied, feed thecontent into the MPEG-4 buffers. From that point, the data flowassociated with the content may be as described by MPEG-4.

-   -   (d) Control of content based on rules.

CMPS 2302 may be used to control usage of content after the initialdecryption, for example, through the use of secure event management asdescribed in the incorporated Ginter '333 patent application. In thecase of MPEG-4 systems, this may require that CMPS 2302 exercise controlover hardware and/or software which performs the following functions:demuxing (performed by Demux 2305), decompression/buffering/decode intoAVOs (performed by Scene Descriptor Graph 2306, AVO Decode 2307 andObject Descriptors 2308), scene rendering (performed in Composite andRender 2309).

CMPS 2302 may also be used to control use and consequences according to:(1) generational copy protection rules such as the CGMS and/or SGMSstandards; (2) various Conditional Access control methods, such as thoseproposed and/or implemented by NDS as described in MPEG-4 documentM2959, DAVIC “Copyright Control Framework” document, and in otherpublications; (3) a Rights Management Language, such as those proposedin the Ginter '333 patent application and/or as described by U.S. Pat.No. 5,638,443 to Stefik, et al.; (4) use policies described inaccordance with AT&T's Policy Maker, as described by Blaze, Feigenbaum,and Lacy; (5) the CCI layer bits for IEEE 1394 serial bus transmissionas specified by the DTDG subgroup of the DVD Copy Protection TechnicalWorking Group and/or as implemented by the Hitachi, Intel, Matsushita,Sony and Toshiba proposed standard (hereafter “the five companyproposal”); (6) controls transmitted using any secure containertechnology such as, for example, IBM Cryptolope; (7) any other means forspecifying use rules and consequences.

-   -   (e) Monitoring use of content.

CMPS 2302 may be used to monitor content to: (i) ensure that rules arebeing complied with; (ii) ensure that no attempts are being made totamper with the system or protected content; and (iii) recordinformation used by rules, including usage information needed forpayment purposes.

-   -   (f) Updating user budgets.

CMPS 2302 may be used to update user or other budgets to reflect usage.

-   -   (g) Exhaust information.

CMPS 2302 may be used to output payment and usage information (“exhaustinformation”) to external processes, including one or more CommerceUtility Systems.

-   -   (h) Hardware identification and configuration.    -   (i) Obtaining new, additional, and/or augmented rules from an        external process, one non-limiting example of which is a Rights        and Permission Clearinghouse as described in the incorporated        Shear patent application.    -   (j) Receiving keys, digital credentials, such as certificates,        and/or administrative information, from certifying authorities,        deployment managers, clearinghouses, and/or other trusted        infrastructure services.    -   (k) Securely sending and/or receiving user and/or appliance        profiling and/or attribute information.    -   (l) Securely identifying a user or a member of a class of users        who requests content and/or CMPO and/or CMPS usage.    -   (m) Securely certifying or otherwise guaranteeing the        authenticity of application code, for example certifying within        CMPO 2301 and/or CMPS 2302 that application code containing        rules and/or other application information, such as information        written in Java code for conditional execution within a Commerce        Appliance, and/or that executes at least in part outside of CMPO        2301 and/or CMPS 2302, has not been altered and/or has been        delivered by a guaranteed (e.g., trusted) party.    -   (n) Securely processing independently delivered CI, such as        described in the incorporated Ginter '333 patent application, to        perform content usage control that protects the rights of        plural, independent parties in a commerce value chain.    -   (O) Securely performing watermarking (including, for example        fingerprinting) functions, for example as described in the        Ginter '333 patent application and as incorporated herein, for        example including interpreting watermarking information to        control content usage and/or to issue an event message, wherein        such event message may be reported back to a remote authority,        such as, for example, a MCMFO rights clearinghouse management        location.

CMPS 2302 may be used to identify and record the current hardwareconfiguration of the Commerce Appliance and any connected devices (e.g.,which loudspeakers are available, identification of attached monitors,including whether particular monitors have digital output ports, etc.)If attached devices (such as loudspeakers) also include CMPSs, the CMPSsmay be used to communicate for purposes of coordination (e.g., a CMPS ina set-top box and/or loudspeaker arrangement may communicate with a CMPSin a downstream digital television or other display device to establishwhich CMPS will be responsible for governance or the nature ofcooperative governance through a virtual rights process, said processoptionally involving a rights authority server that may find, locate,provide, aggregate, distribute, and/or manage rights processes, such asdescribed in the aforementioned Shear patent application, for employingplural CMPSs, for example, for a single user content processing andusage arrangement).

The present invention includes arrangements comprising plural CommerceAppliances and/or CMPSs in one or more user locations, non-limitingexamples of which include a home, apartment, loft, office, and/orvehicle, such as a car, truck, sports utility vehicle, boat, ship, orairplane, that may communicate among themselves at least occasionallyand may comprise a virtual network that operates in a logicallycooperative manner, through at least in part the use of such CMPSs, toensure optimal commercial flexibility and efficiency and the enforcementof rights of commerce value chain participants, including financial andcopyright rights of providers, infrastructure rights of applianceproviders, societal rights of government and/or societal bodies, andprivacy rights of all parties, including consumers. Information relatedto interaction among such a network of value chain participants,including content usage auditing, content usage consequence, and CIspecification, can be securely, variably reported to parties havingright to such information, through, at least in part, use of such CMPSs,for example, as described in the aforementioned Ginter '712 patentapplication regarding the information reporting functioning of VDEnodes.

In one embodiment, shown in FIG. 24, CMPS 2401 consists ofspecial-purpose hardware and resident software or firmware. Theseinclude the following:

-   -   (a) One or more processors or microcontrollers e.g. CPU 2402.        CPU 2402 controls the overall processing of CMPS 2401, including        execution of any necessary software.    -   (b) One or more external communications ports, e.g., Port 2403.        Port 2403 communicates with External Network 2404, which may        include LANs, WANs or distributed networks such as the Internet.        External communications ports may also include one or more IEEE        1394 serial bus interfaces.    -   (c) Memory 2405. Types of memories which may be included in        Memory 2405—and examples of the information they may store—are        the following:        -   i. ROM 2406. ROM 2406 may include any information which is            permanently stored in CMPS 2401, such as (1) CMPS Operating            System 2407 and/or CMPS BIOS 2408, (2) Rules/Controls 2409            which are permanently stored in the CMPS; (3) Control            Primitives 2410 which may be used to build rules or            controls; (4) Keys 2411 associated with the CMPS, including            a Public/Private Key Pair; (5) one or more Certificates 2412            designed to identify CMPS 2401 and/or the device, including            version information; (6) Hardware Signature Information 2413            used to check for tampering (e.g., a hashed signature            reflecting the expected hardware state of the device).        -   ii. RAM 2414. RAM 2414 may hold current state information            needed by CMPS 2401, as well as information temporarily            stored by CMPS 2401 for later use. Information stored in RAM            2414 may include the following: (1) Software 2415 currently            executing in CPU 2402; (2) CMPOs 2416 which are currently            active; (3) Content Object Identification 2417 of those            content objects which are currently active (in an MPEG 4            system this would constitute, for example, an identification            of active AVOs); (4) Rules 2418 which are currently            active; (5) State Information 2419 regarding the current            state of use of content, including an identification of any            higher-order organization (in an MPEG-4 system this would            constitute an identification of the scene descriptor tree            and the current state of composition and rendering); (6)            Stored Exhaust Information 2420 relating to use and/or the            user, designed for external transmission; (7) Updated Budget            Information 2421; (8) Content 2422; (9) Active Content Class            Information 2423; and (10) Active User Identification 2424,            including identification characteristic information.        -   iii. NVRAM 2425 (e.g., flash memory). This type of memory            may hold information which is persistent but changeable,            including at least some: (1) Budget Information 2426; (2)            User Information 2427, such as identification, credit card            numbers; preferred clearinghouses and other Commerce Utility            Systems; (3) User Preferences 2428, such as preferences,            profiles, and/or attribute information; and (4) Appliance            Information 2429, such as attribution and/or state            information.

The types of information described above and stored in CMPS Memory 2405may be stored in alternative of the above memory types, for example,certain budget information may be located in ROM, information regardingspecific one or more clearinghouses may be stored in ROM, certain activeinformation may be moved into NVRAM, etc.

Budget information may include stored budgets made up of, for example:

-   -   (1) electronic cash;    -   (2) pre-authorized uses (e.g., based on a prepayment, the user        has the right to watch 12 hours of programming).    -   (3) Security budgets related to patterns reflecting abnormal        and/or unauthorized usage, for example, as described in the        incorporated Shear patent, wherein such budgets restrict and/or        report certain cumulative usage conduct.    -   (4) electronic credit, including credit resulting from usage        events such as attention to promotional material and/or the        playing of multiple works from one or more classes of works        (e.g., certain publisher's works) triggering a credit or cash        refund event and/or a discount on future playing of one or more        of such publisher's works, such as other works provided by such        publisher.

User information may include the following types of information for oneor more authorized users of the Commerce Appliance:

-   -   (1) Name, address, telephone number, social security number or        other identifier    -   (2) Information used to authenticate the user, which may include        a user selected password and/or biometric data, such as        fingerprints, retinal data, etc.    -   (3) User public/private key pair    -   (4) User attribute and/or profiling information.        -   iv. Removable Memory 2430. This may include any type of            removable memory storage device, such as smart cards, floppy            disks or DVD disks. If the commerce appliance is designed to            play content received on removable memory devices (e.g., a            DVD player), that capability may be used for purposes of the            CMPS.

Memory 2405 may include a protected database, in which certain control,budget, audit, security, and/or cryptographic information is stored insecure memory, with complete information stored in an encrypted fashionin unsecure memory.

-   -   (d) Encryption/Decryption Engine 2431. CMPS 2401 must include a        facility for decrypting received information, including content        and CMPOs and/or other. CMPS 2401 may also include a facility        for encrypting information if such information is to be        transmitted outside the secure boundaries of CMPS 2401. This may        include exhaust sent to clearinghouses or other external        repositories; and content sent across unsecured buses for usage,        such as content sent across IEEE 1394 Serial Bus 2432 to a        computer central processing arrangement or to a viewing device        such as a monitor, wherein a receiving CMPS may be employed to        control such content's usage, including, for example, decrypting        such content, as appropriate. Encryption/Decryption Engine 2431        may include a Random Number Generator 2433 used for the creation        of keys or key pairs that can be used to identify and assure the        uniqueness of CMPSs and support the opening of secure        communication channels between such secure content control        secure encryption/decryption arrangements.    -   (e) Secure Clock/Calendar 2434. CMPS 2401 may include Secure        Clock/Calendar 2434 designed to provide absolute information        regarding the date and time of day, information regarding        elapsed absolute time, and/or relative timing information used        to determine the elapsed time of operations performed by the        system. Secure Clock/Calendar 2434 may include Battery Back Up        2435. It may further include Sync Mechanism 2436 for        synchronization with outside timing information, used to recover        the correct time in the event of a power loss, and/or to check        for tampering.    -   (f) Interface 2437 to blocks used for content rendering and        display. This interface is used for controlling rendering and        display, based on rules, and for obtaining feedback information,        which may be used for budgeting purposes or for providing        information to outside servers (e.g., information on which        content was actually displayed, which choices the user invoked,        etc.) In the case of an MPEG-4 player such as is shown in FIG.        23, this may include control over Commerce Appliance circuitry        which handles, for example, buffering, the scene descriptor        graph, AVO decode, object descriptors and composite and        rendering (e.g., Control Lines 2310, 2311 and 2312).

Feedback Path 2313 from Composite and Render block 2309 may allow CMPS2302 to determine whether and when content has actually been released tothe viewer. For example, Composite and Render block 2309 can issue astart event to CMPS 2302 when an AVO object is released for viewing, andcan issue a stop event to CMPS 2302 when the AVO object is no longerbeing viewed.

Feedback from Composite and Render block 2309 may also be used to detecttampering, by allowing CMPS 2302 to match the identification of theobjects actually released for viewing with the identification of theobjects authorized for release. Start and end time may also be comparedwith the expected elapsed time, with a mismatch possibly indicative ofthe occurrence of an unauthorized event.

In one embodiment, the following protocol may be used for feedback data:

start <id>, T, <instance number><clock time><rendering options>

Sent if elementary stream <id> is reachable in the SD-graph at time T,but not at time T−1.

end <id>, T, <instance number><clock time><rendering options>

T constitutes presentation time, clock time constitutes the wall clocktime, including day and date information, and rendering options mayinclude such information as QoS and rate of play (e.g., fast forward).

Sent if elementary stream <id> is reachable in the SD-graph at time T−1but not at time T. A SD-graph stream is reachable if, during traversalof the SD-graph for display update, the renderer encounters a node thatthe SD-graph update stream <id> created or modified. This implies thatall nodes in the tree need an update history list. This list need not beas large as the number of streams. Further, it can be labeled toindicate if the CMPS will be watching for stream, if not labeled it willnot record them. An AV elementary stream is reachable if the stream'scontent was rendered.

For SD-graph update streams, the object instance number is ignored. ForAV streams, the instance number can be used to disambiguate the casewhere the display shows two or more instances of the same data streamsimultaneously. Instance numbers do not have to count up. In this case,they are simply a unique id that allows the CMPS to match a start eventwith an end event.

In a second embodiment, CMPS 2302 may include some special purposehardware in combination with general purpose hardware which is also usedfor other functions of the device. In this embodiment, care must betaken to ensure that commercially trusted CMPS functions are performedin a secure and tamper-resistant manner, despite the use of generalpurpose hardware. Each of the elements recited above may includededicated CMPS functions and general purpose device functions:

-   -   (a) CPU/microcontroller. This may include one or more devices.        If more than one device is included (e.g., a CPU and a DSP, a        math coprocessor or a commerce coprocessor), these devices may        be included within the same package, which may be rendered        tamper-resistant, or the devices may communicate on a secure        bus. The CPU may include two modes: a secure CMPS mode, and an        unsecure general purpose mode. The secure CMPS mode may allow        addressing of secure memory locations unavailable to the        processor in general purpose mode. This may be accomplished, for        example, by circuitry which remaps some of the available memory        space, so that, in unsecure mode, the CPU cannot address secure        memory locations.    -   (b) External communications ports. If the device, for example, a        Commerce Appliance, is capable of receiving content or other        information through a communications port (e.g., a cable        connection, an Internet connection), this communications port        can be used for CMPS purposes. In such a case, CMPS accesses to        the external communications port is preferably designed to avoid        or minimize interference with the use of such port for receipt        of content.    -   (c) Memory. In some applications and embodiments, it is possible        to operate a Commerce Appliance without NVRAM, wherein        information that may be needed for CMPS operation that would        employ NVRAM would be loaded into RAM, as required. ROM, RAM and        NVRAM may be shared between CMPS uses and general uses. This can        be accomplished in any of the following ways, or in a        combination of these ways: (1) Some memory space may be rendered        off-limits to general purpose uses, for example by        remapping; (2) the entirety of the memory may be rendered        secure, so that even portions of the memory being used for        non-secure purposes cannot be observed or changed except in a        secure and authorized manner; (3) CMPS information may be stored        in an encrypted fashion, though this requires at least some RAM        to be secure, since the CMPS will require direct access to        unencrypted information stored in RAM.    -   (d) Encryption/decryption engine. Encryption and decryption        functions, including key generation, may be handled by special        purpose software running on a general purpose processor        arrangement, particularly, for example, a floating point        processor or DSP arrangement. That processor arrangement may        also be used for purposes of decompressing and displaying        content and/or for handling watermarking/fingerprinting        insertion and/or reading. Alternatively, the device may include        native encryption and decryption functions. For example, various        emerging standards may require at least some degree of        encryption and decryption of content designed to be passed        across unsecure buses within and among devices such as DVD        players, such as the “five company proposal” and other IEEE 1394        related initiatives. Circuitry designed to perform such        encryption and decryption may also be usable for CMPS        applications.    -   (e) Secure clock/calendar. The underlying device may already        require at least some clock information. MPEG-4, for example,        requires the use of clock information for synchronization of        Elementary Streams. A secure CMPS clock can also be used for        such purposes.

In a third embodiment, CMPS 2302 can be primarily software designed torun on a general purpose device which may include certain minimalsecurity-related features. In such a case, CMPS 2302 may be received inthe same channel as the content, or in a side-band channel. An I-CMPOand/or other CI may specify a particular type of CMPS, which CommerceAppliance 2301 must either have or acquire (e.g., download from alocation specified by the I-CMPO), or CMPS 2302 may be included, forexample, with an I-CMPO.

A software CMPS runs on the CPU of the Commerce Appliance. This approachmay be inherently less secure than the use of dedicated hardware. If theCommerce Appliance includes secure hardware, the software CMPS mayconstitute a downloadable OS and/or BIOS which customizes the hardwarefor a particular type of commerce application.

In one embodiment, a software CMPS may make use of one or more softwaretamper resistance means that can materially “harden” software. Thesemeans include software obfuscation techniques that use algorithmic meansto make it very difficult to reverse engineer some or all of a CMPS, andfurther make it difficult to generalize from a reverse engineering of agiven one or more CMPS. Such obfuscation is preferably independent ofsource code and object code can be different for different CMPSs anddifferent platforms, adding further complexity and separation of roles.Such obfuscation can be employed “independently” to both CI, such as anCMPO, as well as to some or all of the CMPS itself, thus obscuring boththe processing environment and executable code for a process. Theapproach is also applicable for integrated software and hardwareimplementation CMPS implementations described above. Other tamperresistance means can also be employed, including using “hiding places”for storing certain state information in obscure and unexpectedlocations, such as locations in NV memory used for other purposes, anddata hiding techniques such as watermarking/fingerprinting.

Association of CMPS with a Commerce Appliance

A CMPS may be permanently attached to a particular device, or may bepartially or fully removable. A removable CMPS may include softwarewhich is securely loaded into a Commerce Appliance, and/or removablehardware. A removable CMPS may be personalized to one or more particularusers, including user keys, budget information, preferences, etc.,thereby allowing different users to use the same Commerce Appliancewithout commingling budgets and/or other rights, etc.

A CMPS may be designed for operation with certain types of contentand/or for operation with certain types of business models. A CommerceAppliance may include more than one type of CMPS. For example, aCommerce Appliance designed to accept and display content pursuant todifferent standards may include one CMPS for each type of format. Inaddition, a Commerce Appliance may include a CMPS provided by aparticular provider, designed to preferentially display certain types ofcontent and to preferentially bill for such content through a particularchannel (e.g., billing to one or more particular credit cards and/orusing a particular one or more clearinghouses).

Source of Rules

The CMPS must recognize those rules which are to be applied toparticular content. Such rules may be received by the CMPS from avariety of sources, depending on the particular embodiment used:

-   -   (a) CMPO. The rules may be included within a CMPO (e.g., CMPO        2303) and/or other CI. The CMPO and/or other CI may be        incorporated within a content object or stream (as, e.g., a        header on an MPEG-4 ES), and/or may be contained within a        dedicated content object or stream encoded and received as per        the underlying standard (e.g., an MPEG-4 CMPO ES), and/or may be        received outside the normal content stream, in which event it        may not be encoded as per the underlying standard (e.g., a CMPS        received as an encrypted object through a sideband channel).    -   (b) CMPS. Rules may be permanently and/or persistently stored        within a CMPS, e.g., Rules 2409. A CMPS may include default        rules designed to handle certain situations, for example, where        no CMPO and/or other necessary CI is received (e.g., content        encoded under an earlier version of the standard which did not        incorporate CMPOs, including MPEG-4 version 1). Complete rules        which are stored within the CMPS may be directly or indirectly        invoked by a CMPO and/or other CI. This may occur through the CI        identifying particular rules through a pointer, and/or it may        occur through the CI identifying itself and the general class of        control it requires, with the CMPS then applying particular        rules specific to that CMPS.

Rule “primitives” may also be stored within the CMPS (e.g., ControlPrimitives 2410). The CMPO and/or other CI may invoke these primitivesby including a sequence of macro-type commands, each of which triggers asequence of CMPS primitives.

-   -   (c) User. The user may be given the ability to create rules        relating to the particular user's preferences. Such rules will        generally be allowed to further restrict the use of content, but        not to expand the use of content beyond that which would        otherwise be allowed. Examples include: (a) rules designed to        require that certain types of content (e.g., adult movies) only        be accessible after entry of a password and/or only to certain        CMPS users (e.g. adults, not children, as, for example,        specified by parents and/or a societal body such as a government        agency); (b) rules designed to require that only particular        users be allowed to invoke operations requiring payment beyond a        certain limit and/or aggregate payment over a certain amount.

The user may be allowed to create templates of rules such as describedin the aforementioned Ginter '333 patent application (and incorporatedherein). In addition, a CMPS arrangement, and/or a particular CMPOand/or other CI, may restrict the rules the user is allowed to specify.For example, a CI may specify that a user can copy a work, but cannotadd rules to the work restricting the ability of a recipient to makeadditional copies (or to be able to view, but only after a payment tothe first user). User supplied one or more rules may govern the useof—including privacy restrictions related to—payment, audit, profiling,preference, and/or any other kind of information (e.g., informationresult as a consequence of the use of a CMPS arrangement, including, forexample, use of secured content). Such user supplied one or more rulescan be associated with the user and/or one or more Commerce Appliancesin a user arrangement, whether or not the information is aggregatedaccording to one or more criteria, and whether or not user and/orappliance identification information is removed during aggregationand/or subsequent reporting, distribution, or any other kind of use.

The ability to allow the user to specify rules allows the CMPS tosubsume (and thereby replace) V-chips, since a parent can use contentrating information to specify precisely what types of information eachviewer will be allowed to watch (e.g., violent content can only bedisplayed after entry of a certain password and/or other identifier,including, for example, insertion of a removable hardware card (smart orrights card) possessed by a user).

-   -   (d) External network source. The rules may be stored on an        external server. Rules may be addressed and downloaded by the        CMPS if necessary (e.g., either the CMPO and/or other CI and/or        the CMPS contains a pointer to certain rules location(s), such        as one or more URLs). In addition, content providers and/or        clearinghouses may broadcast rules designed for general        applicability. For example, a content provider might broadcast a        set of rules providing a discount to any user participating in a        promotional event (e.g., by providing certain user information).        Such rules could be received by all connected devices, could be        received by certain devices identified as of interest by the        content provider (e.g., all recent viewers of a particular        program, as identified by exhaust information provided by the        CMPS to a clearinghouse and/or all members having certain        identity characteristics such as being members of one or more        classes) and/or could be posted in central locations.

EXAMPLE EMBODIMENT

In one embodiment, a set of MPEG-4 Elementary Streams may make up awork. The Elementary Streams may be encrypted and multiplexed togetherto form an Aggregate Stream. One or more CMPOs may be present in suchstream, or may otherwise be associated with the stream. Options are asfollows:

1. Content may be streamed or may be received as static data structures.

2. A Work may be made up of a single stream or data structure, or ofmany separately addressable streams or data structures, each of whichmay constitute an Object.

3. If a Work is made up of separately addressable streams or datastructures, those streams or data structures may be multiplexed togetherinto an Aggregate Stream, or may be received separately.

4. If streams or data structures are multiplexed together into anAggregate Stream, the streams or data structures may be encrypted priorto such multiplexing. The Aggregate Stream itself may be encrypted,whether or not the underlying streams or data structures are encrypted.The following possibilities therefore exist: (a) individual streams/datastructures are unencrypted (in the clear), the Aggregate Stream isunencrypted; (b) individual streams/data structures are unencryptedprior to multiplexing, the Aggregate Stream is encrypted followingmultiplexing; (c) individual streams/data structures are encrypted priorto multiplexing, the Aggregate Stream is not encrypted followingmultiplexing; or (d) individual streams/data structures are encryptedprior to multiplexing, the Aggregate Stream is encrypted followingmultiplexing.

5. A CMPO may be associated with a channel (CCMPO), a work (MCMPO) or anindividual Object (CMPO).

6. A CMPO may be received prior to the controlled data, may be receivedcontemporaneously with the data, or may be received after the data (inwhich event use of the data must wait until the CMPO has been received).

7. A CMPO may be received as part of an Aggregate Stream or separately.

8. If a CMPO is received as part of the Aggregate Stream, it may bemultiplexed together with the individual streams or data structures, ormay constitute a separate stream or data structure.

9. If a CMPO is multiplexed within the Aggregate Stream, it may beencrypted or nonencrypted. If encrypted, it may be encrypted prior tomultiplexing, and/or encrypted after multiplexing, if the entireAggregate Stream is encrypted.

10. If a CMPO is received as part of the Aggregate Stream, it may be (a)a part of the stream or data structure which holds the content (e.g., aheader); (b) a separate stream or data structure encoded pursuant to thesame format as the streams or data structures which hold the content(e.g., an MPEG-4 ES) or (c) a separate stream or data structure encodedunder a different format designed for CMPOs.

11. If a CMPO is a part of the stream or data structure which holds thecontent, it may be (a) a header which is received once and thenpersistently maintained for control of the content; (b) a header whichis received at regular intervals within the stream or data structure; or(c) data distributed throughout the stream or data structure.

These various scenarios give rise to different requirements fordemultiplexing and decryption of the CMPOs. FIG. 25 illustrates thefollowing embodiment:

1. Aggregate Stream 2501 is made up of multiplexed ESs (e.g., ES 2502and 2503). A combination of such ESs makes up a single work. AggregateStream 2501 is generated by a cable aggregator and received by a user'sset-top box as one of a number of channels.

2. CCMPOs 2504 corresponding to each channel are sent along the cable inHeader 2505 at regular intervals (e.g., once per second). When theset-top box is turned on, it polls each channel, and downloads allcurrent CCMPOs. These are stored persistently, and are changed only if anew CCMPO is received which differs from prior CCMPOs.

3. When the user selects a channel, the set-top box addresses theassociated CCMPO. The CCMPO may specify, for example, that content inthis particular channel may only be accessed by subscribers to thechannel. A CMPS within the set-top box accesses a user profilepersistently stored in NVRAM and determines that the user is asubscriber. The CMPS deems the CCMPO rule to have been satisfied.

4. The CMPS obtains an identifier for the MCMPO associated with the work(video) currently streaming on the channel and a key for the MCMPO. Ifworks are received serially on the channel (e.g., a television channelin which one work is provided at a time), the received MCMPO identifiermay include don't care bits so that it can address any MCMPO currentlyon the channel.

5. The CMPS begins demuxing of Aggregate Stream 2501 (this may occur inparallel with the preceding step), and obtains the MCMPO, which isencoded into an ES multiplexed within the Aggregate Stream (e.g., MCMPO2506). Although each ES within Aggregate Stream 2501 has been encrypted,Aggregate Stream 2501 was not encrypted following multiplexing. Thisallows the CMPS to demultiplex Aggregate Stream 2501 without decryptingthe entire Aggregate Stream.

6. The CMPS identifies the ES which constitutes the MCMPO (e.g., ES2503). The CMPS downloads one complete instance of MCMPO 2506 into aninternal buffer, and uses the key received from CCMPO 2504 to decryptMCMPO 2506.

7. The CMPS determines which rules are applied by MCMPO 2506. MCMPO 2506might, for example, include a rule stating that the user can view theassociated work with advertisements at a low fee, but must pay a higherfee for viewing the work without advertisements.

8. The CMPS generates an options menu, and displays that menu on thescreen for the user. The menu specifies the options, including the costfor each option. Additional options may be specified, including paymenttypes.

9. The user uses a remote control pointing device to choose to view thework at a lower cost but with advertisements. The user specifies thatpayment can be made from an electronic cash budget stored in the CMPS.

10. The CMPS subtracts the specified amount from the budget persistentlystored in NVRAM, and generates and encrypts a message to a serverassociated with the cable. The message transfers the required budget tothe server, either by transferring electronic cash, or by authorizing afinancial clearinghouse to transfer the amount from the user's accountto the cable provider's. This message may be sent immediately, or may bebuffered to be sent later (e.g., when the user connects the device tothe Internet). This step may be taken in parallel with decryption of thecontent.)

11. The CMPS obtains from MCMPO 2506 a set of keys used to decrypt theElementary Streams associated with the work (e.g., ES 2502). The CMPSalso obtains identifiers for the specific ESs to be used. Since the userhas indicated that advertisements are to be included, the MCMPOidentifies ESs associated with the advertisements, and identifies aScene Descriptor Graph which includes advertisements. A Scene DescriptorGraph which does not include advertisements is not identified, and isnot passed through by the CMPS.

12. The CMPS passes the decrypted ESs to the MPEG-4 buffers. The normalprocess of MPEG-4 decoding, compositing and rendering then takes place.The Composite and Render block outputs Start and Stop events for eachobject released for viewing. The CMPS monitors this information andcompares it to the expected events. In particular, the CMPS confirmsthat the advertisements have been released for viewing, and that eachoperation has occupied approximately the expected amount of time.

In another embodiment, a set-top box containing a CMPS (e.g., CMPS 2302from FIG. 23) may have a cable input (e.g., carrying M4 Bit Streams 2314and CMPOs 2303). The cable may carry multiple channels, each made up oftwo sub-channels, with one sub-channel carrying MPEG-4 ESs (e.g., M4 BitStreams 2314), and the other sub-channel carrying CMPOs (e.g., CMPOs2303). The sub-channel carrying CMPOs 2303 could be routed directly toCMPS 2302, with the ES channel being routed to a decryption block(operating under control of the CMPS, e.g., CR&D 2315), and then to theMPEG-4 buffers (e.g., buffers associated with Scene Descriptor Graph2306, AVO Decode 2307 and Object Descriptors 2308). In this case, if theESs are not encrypted, they proceed unchanged through the decryptionblock and into the buffers. This may occur, for example, if the ESs arebeing broadcast for free, with no restrictions, and/or if they arepublic domain information, and/or they were created prior to inclusionof CMPOs in the MPEG-4 standard.

Such an embodiment might include timing synchronization information inthe CMPO sub-channel, so that CMPOs can be synchronized with theassociated ESs.

The concept of incorporating two separate streams, one consisting ofcontrol information and connected directly to the CMPS, and the otherconsisting of ESs, may support a high degree of modularization, suchthat the formats of CMPOs, and particular types of CMPS's, may bechanged without alteration to the underlying ES format. For example, itmay be possible to change the CMPO format without the necessity forreformatting content ESs. To take another example, it may be possible toupgrade a Commerce Appliance by including a new or different CMPS,without the necessity for any changes to any of the circuitry designedto demultiplex, composite and render the content ESs. A user mightobtain a CMPS on a smart card or other removable device, and plug thatdevice into a Commerce Appliance. This could be done to customize aCommerce Appliance for a particular application or for particularcontent. the user that necessary hardware is missing; or (3) causing agraceful rejection of the disk, including informing the user of thereason for the rejection.

To take another example, a CMPO and/or other CI may include a businessmodel which allows the user to choose among quality levels (or otherforms of variations of a given work, for example, longer length and/orgreater options), with a higher price being charged if the user selectsa higher level of quality (e.g., music may be played at low resolutionfor free, but requires a payment in order to be played at a higherresolution). In such a case, the Commerce Appliance may not includeloudspeakers which are capable of outputting sound at the higherresolution. The CMPS arrangement preferably identifies this situation,and either eliminates the higher resolution output as an option for theuser, or informs the user that this option costs more but provides noadditional benefit given the Commerce Appliance's current functionalityor given the Commerce Appliance not being docked in a user arrangementthat provides higher quality loudspeakers.

If the Commerce Appliance may be hooked up to external devices (e.g.,loudspeakers, display, etc.), the CMPS will require some mechanism foridentifying and registering such devices. Each device may be used tomake standard ID and capability information available at all times,thereby allowing the CMPS to poll all connected devices at regularintervals, including, for example, authenticating CMPS arrangementswithin one or more of each such connected devices. Using anotherapproach, all devices could be used to output CMPS identificationinformation upon power-on, with later connected devices being used tooutput such information upon establishment of the connection. Suchidentification information may take the form, for example, ofauthentication information provided under the “five companyarrangement”, such authentication methods are herein incorporated byreference.

As discussed earlier, a Commerce Appliance may be connected to multipledevices each containing its own CMPS arrangement (e.g., a DVD player maybe connected to a digital TV) In such cases, the CMPSs must be able toinitiate secure communication (e.g., using a scheme, for example, likethe “five company proposal” for IEEE 1394 serial bus) and determine howthe CMPSs will interact with respect to content communication betweenCMPSs and, in certain embodiments, regarding cooperative governance ofsuch content such as describing in the incorporated Shear patentapplication. In one embodiment, the first CMPS arrangement to receivecontent might govern the control process by downloading an initial CMPOand/or other CI, and display one or more of the rules to the user, etc.The second CMPS arrangement might recognize that it has no further roleto play, either as a result of a communication between the two CMPSarrangements, or as a result of changes to the content stream created bythe first CMPS arrangement (which decrypted the content, and may haveallowed demuxing, composition and rendering, etc.)

The relationship between upstream and downstream CMPSs arrangements maybe complicated if one device handles certain aspects of MPEG-4rendering, and the other handles other aspects. For example, a DVDplayer might handle demuxing and buffering, transferring raw ESs to adigital TV, which then handles composition and rendering, as well asdisplay. In such a case, there might be no back-channel from thecomposition and rendering block to the upstream CMPS arrangement. CMPSarrangements are preferably designed to handle stand-alone cases (a DVD(or any other optical disk) player with a CMPS arrangement attached to adumb TV with no CMPS), multiple CMPS arrangement cases in which one CMPSarrangement handles all of the processing (a DVD (or other optical disk)player which handles everything through composition and rendering, witha video stream output to the digital TV (in one non-limiting example,via an IEEE 1349 serial bus) (that output stream would be encrypted asper the “five company proposal” for copy protection using IEEE 1394serial bus transmission)) and/or shared processing between two or moreCMPSs arrangements regarding some, or in certain cases, all, of suchprocessing.

2. Initialization of a Particular Content Stream.

The CMPS may be designed so that it can accept initializationinformation which initializes the CMPS for a particular content streamor channel. This header, which may be a CMPO and/or other CI, maycontain information used by the CMPS to locate and/or interpret aparticular content stream as well as CI associated with that stream.This initial header may be received through a sideband channel, or maybe received as a CI ES such as a CMPO ES.

In one example, shown in FIG. 26, Header CMPO 2601 may include thefollowing information:

-   -   (a) Stream/Object/CMPO ID 2602, which identifies the content        streams/objects governed by Header CMPO 2601 and/or        identification of CMPOs associated with each such content stream        or object.

In one embodiment, Header CMPO 2601 identifies other CMPOs which containrules and keys associated with particular content streams. In anotherembodiment, Header CMPO 2601 directly controls all content streams, byincorporating the keys and rules associated with such streams. In thelatter case, no other CMPOs may be used.

In one embodiment, Header CMPO 2601 may be one or more CMPOs, CCMPOs,MCMPOs, and/or other CI.

-   -   (b) One or CMPO Keys 2603 for decrypting each identified CMPO.    -   (c) Work-Level Control 2604, consisting of basic control        information associated with the work as a whole, and therefore        potentially applicable to all of the content streams which make        up the work. This basic control information may include rules        governing the work as a whole, including options to be presented        to the user.    -   (d) In one embodiment of this embodiment, a header CMPO may be        updatable to contain User/Site Information 2605 regarding a        particular user or site currently authorized to use certain        content, as well as one or more rule sets under which the user        has gained such authorization. A header CMPO associated with a        work currently being viewed may be stored in RAM or NVRAM. This        may include updated information. In one embodiment, the CMPO may        also store header CMPOs for certain works viewed in the past. In        one embodiment, header CMPOs may be stored in non-secure memory,        with information sufficient to identify and authenticate that        each header CMPO had not been changed.

In one such header CMPO embodiment of this embodiment, the header CMPOoperates as follows:

-   -   (a) The header CMPO is received by a CMPS arrangement. In the        case of previously unreceived content which has now become        available, the header CMPO may be received at an input port. In        the case of content which is already available, but is not        currently being used (e.g., a set-top box with 500 channels, of        which either 0 or 1 are being displayed at any given time),        CCMPOs for each channel may be buffered by the CMPS arrangement        for possible use if the user invokes particular content (e.g.,        switches to a particular channel).

In either case, the header CMPO must include information which allows aCMPS arrangement to identify it as a header CMPO.

-   -   (b) The CMPS arrangement obtains business-model information held        in the clear in the header CMPO. Business-model information may        include, for example, a statement that content can be viewed for        free if advertisements are included, or if the user authorizes        Nielson-type information, user and/or audience measurement        information, for example, content may be output to a server or        otherwise copied once, but only at a price.    -   (c) The CMPS arrangement either accepts the business model, if        the user has authorized it to accept certain types of models        (e.g., the user has programmed the CMPS arrangement to always        accept play with advertisements for free), rejects the business        model, if the user has instructed that the particular model        always be rejected, or displays the business model to the user        (e.g., by presenting options on the screen).    -   (d) If a business model has been accepted, the CMPS arrangement        then decrypts the remainder of the header CMPO. If the Commerce        Appliance contains a live output connection to an external        server (e.g., Internet connection, back-channel on a set-top        box, etc.), and if latency problems are handled, decryption of        these keys can be handled by communicating with the external        server, each side authenticating the other, establishment of a        secure channel, and receipt of a key from the server. If the        Commerce Appliance is not at least occasionally connected to an        external server, decryption may have to be based on one or more        keys securely stored in the Commerce Appliance.    -   (e) Once a header CMPO has been decrypted, the CMPS arrangement        acquires information used to identify and locate the streams        containing the content, and keys which are used to decrypt        either the CMPOs associated with the content, or to directly        decrypt the content itself.    -   (f) In one embodiment of this header embodiment, the header CMPO        may contain a data structure for the storage of information        added by the CMPS arrangement. Such information may include the        following:        -   (1) Identification of user and/or Commerce Appliance and/or            CMPS arrangement. In this embodiment, such information may            be stored in a header CMPO in order to provide an audit            trail in the event the work (including the header CMPO) is            transferred (this only works if the header CMPO is            transferred in a writable form). Such information may be            used to allow a user to transfer the work to other Commerce            Appliances owned by the user without the payment of            additional cost, if such transfers are allowed by rule            information associated with the header CMPO. For example, a            user may have a subscription to a particular cable service,            paid for in advance by the user. When a CMPS arrangement            downloads a header CMPO from that cable service, the CMPS            arrangement may store the user's identification in the            header CMPO. The CMPS arrangement may then require that the            updated header CMPO be included if the content is copied or            transferred. The header CMPO could include a rule stating            that, once the user information has been filled in, the            associated content can only be viewed by that user, and/or            by Commerce Appliances associated with that user. This would            allow the user to make multiple copies of the work, and to            display the work on multiple Commerce Appliances, but those            copies could not be displayed or used by non-authorized            users and/or on non-authorized Commerce Appliances. The            header CMPO might also include a rule stating that the user            information can only be changed by an authorized user (e.g.,            if user 1 transfers the work to user 2, user 2's CMPS            arrangement can update the user information in the header            CMPO, thereby allowing user 2 to view the work, but only if            user 2 is also a subscriber to the cable channel).        -   (2) Identification of particular rules options governing            use. Rule sets included in header CMPOs may include options.            In certain cases, exercise of a particular option might            preclude later exercise of a different option. For example,            a user might be given the choice to view an unchanged work            for one price, or to change a work and view the changed work            for a higher price. Once the user decides to change the work            and view the changed work, this choice is preferably stored            in the header CMPO, since the option of viewing the original            unchanged work at the lower price is no longer available.            The user might have further acquired the right, or may now            be presented with the option for the right, to further            distribute the changed work at a mark-up in cost resulting            in third party derived revenue and usage information flowing            to both the user and the original work stakeholder(s).        -   (3) Historical usage information. The header CMPO may            include information relating to the number and types of            usages. For example, if the underlying work is copied, the            header CMPO may be updated to reflect the fact that a copy            has been made, since a rule associated with the work might            allow only a single copy (e.g., for backup and/or            timeshifting purposes). To take another example, a user            might obtain the right to view a work one time, or for a            certain number of times. The header CMPO would then be            updated to reflect each such use.

Usage information may be used to determine if additional uses areauthorized by rules associated with the header CMPO. Such informationmay also be used for audit purposes. Such information may also beprovided as usage information exhaust, reported to an external server.For example, a rule may specify that a work may be viewed for free, butonly if historical usage information is downloaded to a server.

Content Management Protection Objects (CMPO)

The Content Management and Protection Object (“CMPO”) is a datastructure which includes information used by the CMPS to govern use ofcertain content. A CMPO may be formatted as a data structure specifiedby a particular standard (e.g., an MPEG-4 ES), or may be formatted as adata structure not defined by the standard. If the CMPO is formatted asa data structure specified by the standard, it may be received in thechannel utilized by the standard (e.g., as part of a composite MPEG-4stream) or may be received through some other, side-band method. If theCMPO is formatted as a data structure not specified by the relevantstandard, it is provided and decoded using some side-band method, whichmay include receipt through the same port as formatted content and/ormay include receipt through a separate port.

Content may be controlled at virtually any level of granularity. Threeexemplary levels will be discussed herein: “channel,” “work,” and“object.”

A “channel” represents an aggregation of works. The works may beavailable for selection by the user (e.g., a web site, or a videolibrary) or may be received serially (e.g., a cable television channel).

A “work” represents a single audio-visual, textual or other work,intended to be consumed (viewed, read, etc.) by a user as an integratedwhole. A work may, for example, be a movie, a song, a magazine article,a multimedia product such, for example, as sophisticated videogame. Awork may incorporate other works, as, for example, in a multimedia workwhich incorporates songs, video, text, etc. In such a case, rights maybe associated

An “object” represents a separately addressable portion of a work. Anobject may be, for example, an individual MPEG-4 AVO, a scene descriptorgraph, an object descriptor, the soundtrack for a movie, a weapon in avideogame, or any other logically definable portion.

Content may be controlled at any of these levels (as well asintermediate levels not discussed herein). The preferred embodimentmechanism for such control is a CMPO or CMPO arrangement (whichcomprises one or more CMPOs, and if plural, then plural, cooperatingCMPOs). CMPOs and CMPO arrangements may be organized hierarchically,with a Channel CMPO arrangement imposing rules applicable to allcontained works, a MCMPO or an SGCMPO imposing rules applicable to allobjects within a work, and a CMPO arrangement imposing rules applicableto a particular object.

In one embodiment, illustrated in FIG. 27, a CMPS may download CCMPO2701. CCMPO 2701 may include one or more Rules 2702 applicable to allcontent in the channel, as well as one or more Keys 2703 used fordecryption of one or more MCMPOs and/or SGCMPOs. MCMPO 2704 may includeRules 2705 applicable to a single work and/or works, one or more classesand/or more users and/or user classes, and may also include Keys 2706used to decrypt CMPOs. CMPO 2707 may include Rules 2708 applicable to anindividual object, as well as Key 2709 used to decrypt the object.

As long as all objects are subject to control at some level, there is norequirement that each object be individually controlled. For example,CCMPO 2701 could specify a single rule for viewing content contained inits channel (e.g., content can only be viewed by a subscriber, who isthen might be free to redistribute the content with no furtherobligation to the content provider). In such a case, rules would notnecessarily be used for MCMPOs (e.g. Rules 2705), SGCMPOs, or CMPOs(e.g., Rules 2708). In one embodiment, MCMPOs, SGCMPOs, and CMPOs couldbe dispensed with, and CCMPO 2701 could include all keys used to decryptall content, or could specify a location where such keys could belocated. In another embodiment, CCMPO 2701 would supply Key 2703 used todecrypt MCMPO 2704. MCMPO 2704 might include keys used to decrypt CMPOs(e.g., Keys 2706), but might include no additional Rules 2705. CMPO 2707might include Key 2709 used to decrypt an object, but might include noadditional Rules 2708. In certain embodiments, there may be no SGCMPOs.

A CMPO may be contained within a content data structure specified by arelevant standard (e.g., the CMPO may be part of a header in an MPEG-4ES.) A CMPO may be contained within its own, dedicated data structurespecified by a relevant standard (e.g., a CMPO ES). A CMPO may becontained within a data structure not specified by any content standard(e.g., a CMPO contained within a DigiBox).

A CCMPO may include the following elements:

-   -   (a) ID 2710. This may take the following form: <channel ID><CMPO        type><CMPO ID><version number>. In the case of hierarchical CMPO        organization (e.g., CCMPOs controlling MCMPOs controlling        CMPOs), CMPO ID 2711 can include one field for each level of the        hierarchy, thereby allowing CMPO ID 2711 to specify the location        of any particular CMPO in the organization. ID 2710 for a CCMPO        may, for example, be 123-000-000. ID 2712 for a MCMPO of a work        within that channel may, for example, be 123-456-000, thereby        allowing the specification of 1,000 MCMPOs as controlled by the        CCMPO identified as “123.” CMPO ID 2711 for a CMPO associated        with an object within the particular work may, for example, be        123-456-789, thereby allowing the specification of 1,000 CMPOs        as associated with each MCMPO.

This method of specifying CMPO IDs thereby conveys the exact location ofany CMPO within a hierarchy of CMPOs. For cases in which higher levelsof the hierarchy do not exist (e.g., a MCMPO with no associated CCMPO),the digits associated with that level of the hierarchy may be specifiedas zeroes.

-   -   (b) Rules 2702 applicable to all content in the channel. These        may be self-contained rules, or may be pointers to rules        obtainable elsewhere. Rules are optional at this level.    -   (c) Information 2713 designed for display in the event the user        is unable to comply with the rules (e.g., an advertisement        screen informing the user that a subscription is available at a        certain cost, and including a list of content available on the        channel).    -   (d) Keys 2703 for the decryption of each MCMPO controlled by        this CCMPO. In one embodiment, the CCMPO includes one or more        keys which decrypt all MCMPOs. In an alternate embodiment, the        CCMPO includes one or more specific keys for each MCMPO.    -   (e) A specification of a CMPS Type (2714), or of        hardware/software necessary or desirable to use the content        associated with this channel.

The contents of a MCMPO may be similar to those of a CCMPO, except thatthe MCMPO may include rules applicable to a single work, and mayidentify CMPOs associated with each object.

The contents of each CMPO may be similar to those of the MCMPO, exceptthat the CMPO may include rules and keys applicable to a single object.

The contents of an SGCMPO may be similar to those of the CCMPO, exceptthat the MCMPO may include rules applicable to only certain one or moreclasses of rights, certain one or more classes of works, and/or to oneor more certain classes of users and/or user arrangements (e.g. CMPOarrangements and/or their devices).

In another embodiment, shown in FIG. 28, CMPO Data Structure 2801 may bedefined as follows:

CMPO Data Structure 2801 is made up of elements. Each element includes aself-contained item of information. The CMPS parses CMPO Data Structure,one element at a time.

Type Element 2802 identifies the data structure as a CMPO, therebyallowing the CMPS to distinguish it from a content ES. In an exemplaryembodiment, this element may include 4 bits, each of which may be set to“1” to indicate that the data structure is a CMPO.

The second element is CMPO Identifier 2803, which is used to identifythis particular CMPO and to convey whether the CMPO is part of ahierarchical organization of CMPOs and, if so, where this CMPO fits intothat organization.

CMPO Identifier 2803 is divided into four sub-elements, each of threebits. These are shown as sub-elements A, B, C and D. The firstsub-element (2803 A) identifies the CMPO type, and indicates whether theCMPO is governed or controlled by any other CMPO:

100: this is a top-level CMPO (associated with a channel or anaggregation of works) and is not controlled by any other CMPO.

010: this is a mid-level CMPO (associated with a particular work) and isnot controlled by any other CMPO.

110: this is a mid-level CMPO, and is controlled by a top-level CMPO.

001: this is a low-level CMPO (associated with an object within a work)and is not controlled by any other CMPO. This case will be rare, since alow-level CMPO will ordinarily be controlled by at least onehigher-level CMPO.

011: this is a low-level CMPO, and is controlled by a mid-level CMPO,but not by a top-level CMPO.

111: this is a low-level CMPO, and is controlled by a top-level CMPO andby a mid-level CMPO.

The second sub-element of CMPO ID 2803 (sub-element B) identifies atop-level CMPO. In the case of a top-level CMPO, this identifier isassigned by the creator of the CMPO. In the case of a mid-level orlow-level CMPO which is controlled by a top-level CMPO, this sub-elementcontains the identification of the top-level CMPO which performs suchcontrol. In the case of a mid-level or low-level CMPO which is notcontrolled by a top-level CMPO, this sub-element contains zeroes.

The third sub-element of CMPO ID 2803 (sub-element C) identifies amid-level CMPO. In the case of a top-level CMPO, this sub-elementcontains zeroes. In the case of a mid-level CMPO, this sub-elementcontains the identification of the particular CMPO. In the case of alow-level CMPO which is controlled by a mid-level CMPO, this sub-elementcontains the identification of the mid-level CMPO which performs suchcontrol. In the case of a low-level CMPO which is not controlled by amid-level CMPO, this sub-element contains zeroes.

The fourth sub-element of CMPO ID 2803 (sub-element D) identifies alow-level CMPO. In the case of a top-level or mid-level CMPO, thissub-element contains zeroes. In the case of a low-level CMPO, thissub-element contains the identification of the particular CMPO.

Following the identifier element is Size Element 2804 indicating thesize of the CMPO data structure. This element contains the number ofelements (or bytes) to the final element in the data structure. Thiselement may be rewritten if alterations are made to the CMPO. The CMPSmay use this size information to determine whether the element has beenaltered without permission, since such an alteration might result in adifferent size. For such purposes, the CMPS may store the informationcontained in this element in a protected database. This information canalso be used to establish that the entire CMPO has been received and isavailable, prior to any attempt to proceed with processing.

Following Size Element 2804 are one or more Ownership/Control Elementscontaining ownership and chain of control information (e.g.,Ownership/Control Elements 2805, 2806 and 2807). In the first suchelement (2805), the creator of the CMPO may include a specificidentifier associated with that creator. Additional participants mayalso be identified in following elements (e.g., 2806, 2807). Forexample, Element 2805 could identify the creator of the CMPO, Element2806 could identify the publisher of the associated work and Element2807 could identify the author of the work.

A specific End Element 2808 sequence (e.g., 0000) indicates the end ofthe chain of ownership elements. If this sequence is encountered in thefirst element, this indicates that no chain of ownership information ispresent.

Chain of ownership information can be added, if rules associated withCMPO 2801 permit such additions. If, for example, a user purchases thework associated with CMPO 2801, the user's identification may be addedas a new element in the chain of ownership elements (e.g., a new elementfollowing 2807, but before 2808). This may be done at the point ofpurchase, or may be accomplished by the CMPS once CMPO 2801 isencountered and the CMPS determines that the user has purchased theassociated work. In such a case, the CMPS may obtain the user identifierfrom a data structure stored by the CMPS in NVRAM.

Following the ownership element chain are one or more Handling Elements(e.g., 2809, 2810) indicating chain of handling. These elements maycontain the identification of any CMPS which has downloaded and decodedCMPO 2801, and/or may contain the identification of any user associatedwith any such CMPS. Such information may be used for audit purposes, toallow a trail of handling in the event a work is determined to have beencirculated improperly. Such information may also be reported as exhaustto a clearinghouse or central server. Chain of handling informationpreferably remains persistent until reported. If the number of elementsrequired for such information exceeds a specified amount (e.g., twentyseparate user identifiers), a CMPS may refuse to allow any furtherprocessing of CMPO 2801 or the associated work until the CMPS has beenconnected to an external server and has reported the chain of handlinginformation.

The last element in the chain of handling elements (e.g., 2811)indicates the end of this group of elements. The contents of thiselement may, for example, be all zeroes.

Following the chain of handling elements may be one or more CertificateElements (e.g., 2812, 2813) containing or pointing to a digitalcertificate associated with this CMPO. Such a digital certificate may beused by the CMPS to authenticate the CMPO. The final element in thedigital certificate chain is all zeroes (2814). If no digitalcertificate is present, a single element of all zeroes exists in thislocation.

Following the Certificate Elements may be a set of Governed ObjectElements (e.g., 2815, 2816, 2817, 2818) specifying one or more contentobjects and/or CMPOs which may be governed by or associated with CMPO2801. Each such governed object or CMPO is identified by a specificidentifier and/or by a location where such object or CMPO may be found(e.g., these may be stored in locations 2815 and 2817). Following eachsuch identifier may be one or more keys used to decrypt such CMPO orobject (e.g., stored in locations 2816 and 2818). The set ofidentifiers/keys ends with a termination element made up of all zeroes(2819).

Following the set of elements specifying identifiers and/or keys may bea set of Rules Elements (e.g., 2820, 2821, 2822) specifyingrules/controls and conditions associated with use of the content objectsand/or CMPOs identified in the Governed Objects chain (e.g., locations2815 and 2817). Exemplary rules are described below. Elements maycontain explicit rules or may contain pointers to rules storedelsewhere. Conditions may include particular hardware resourcesnecessary to use associated content objects or to satisfy certain rules,or particular types of CMPS's which are necessary or preferred for useof the associated content objects.

Following the rules/controls and conditions elements may be a set ofInformation Elements 2823 containing information specified by thecreator of the CMPO. Among other contents, such information may includecontent, or pointers to content, programming, or pointers toprogramming.

The CMPO ends with Final Termination Element 2824.

In one embodiment, the rules contained in Rules Elements 2820-2822 ofCMPO 2801 may include, for example, the following operations:

-   -   (1) Play. This operation allows the user to play the content        (though not to copy it) without restriction.    -   (2) Navigate. This allows the user to perform certain types of        navigation functions, including fast forward/rewind, stop and        search. Search may be indexed or unindexed.    -   (3) Copy. Copy may be allowed once (e.g., time-shifting,        archiving), may be allowed for a specified number of times        and/or may be allowed for limited period of time, or may be        allowed for an unlimited period of time, so long as other rules,        including relevant budgets, are not violated or exceeded. A CMPS        arrangement may be designed so that a Copy operation may cause        an update to an associated CMPO (e.g., including an indication        that the associated content has been copied, identifying the        date of copying and the site responsible for making the copy),        without causing any change to any applicable content object, and        in particular without requiring that associated content objects        be demuxed, decrypted or decompressed. In the case of MPEG-4,        for example, this may require the following multi-stage demux        process:        -   (i) the CMPS arrangement receives a Copy instruction from            the user, or from a header CMPO.        -   (ii) CMPO ESs associated with the MPEG-4 stream which is to            be copied are separated from the content stream in a first            demux stage.        -   (iii) CMPOs are decrypted and updated by the CMPS            arrangement. The CMPOs are then remuxed with the content ESs            (which have never been demuxed from each other), and the            entire stream is routed to the output port without further            alteration.

This process allows a copy operation to take place without requiringthat the content streams be demuxed and decrypted. It requires that theCMPS arrangement include two outputs: one output connected to thedigital output port (e.g., FIG. 23 line 2316, connecting to DigitalOutput Port 2317), and one output connected to the MPEG-4 buffers (e.g.,FIG. 23, lines 2310, 2311, 2312), with a switch designed to send contentto one output or the other (or to both, if content is to be viewed andcopied simultaneously) (e.g., Switch 2319). Switch 2319 can be the onlypath to Digital Output Port 2317, thereby allowing CMPS 2302 to exercisedirect control over that port, and to ensure that content is never sentto that port unless authorized by a control. If Digital Output Port 2317is also the connector to a digital display device, CMPS 2302 will alsohave to authorize content to be sent to that port even if no copyoperation has been authorized.

In one example embodiment, the receiving device receiving theinformation through Digital Output Port 2317 may have to authenticatewith the sending device (e.g., CMPS 2302). Authentication may be for anycharacteristic of the device and/or one or more CMPSs used inconjunction with that device. Thus, for example, a sending appliance maynot transmit content to a storage device lacking a compatible CMPS.

In another non-limiting example, CMPS 2302 can incorporate sessionencryption functionality (e.g., the “five company arrangement”) whichestablishes a secure channel from a sending interface to one or moreexternal device interfaces (e.g., a digital monitor), and provided thatthe receiving interface has authenticated with the sending interface,encrypts the content so that it can only be decrypted by one or moreauthenticated 1394 device interfaces. In that case, CMPS 2302 wouldcheck for a suitable IEEE 1394 serial bus interface, and would allowcontent to flow to Digital Output Port 2317 only if (a) an authorizedPlay operation has been invoked, a secure channel has been establishedwith the device and the content has been session-encrypted, or (b) anauthorized Copy or Retransmit operation has been invoked, and thecontent has been treated as per the above description (i.e., the CMPOhas been demuxed, changed and remuxed, the content has never beendecrypted or demuxed).

This is only possible if CMPOs are separately identifiable at an earlydemux stage, which most likely requires that they be stored in separateCMPO ESs. If the CMPOs are stored as headers in content ESs, it may beimpossible to identify the CMPOs prior to a full demux and decryptoperation on the entirety of the stream.

-   -   (4) Change. The user may be authorized to change the content.    -   (5) Delete. This command allows the user to delete content which        is stored in the memory of the Consumer Appliance. This        operation operates on the entire work. If the user wishes to        delete a portion of a work, the Change operation must be used.    -   (6) Transfer. A user may be authorized to transfer a work to a        third party. This differs from the Copy operation in that the        user does not retain the content or any rights to the content.        The Transfer operation may be carried out by combining a Copy        operation and a Delete operation. Transfer may require        alteration of the header CMPO associated with the work (e.g.,        adding or altering an Ownership/Control Element, such as        Elements 2805-2807 of FIG. 28), so as to associate rights to the        work with the third party.

These basic operations may be subject to modifications, which mayinclude:

-   -   i. Payment. Operations may be conditioned on some type of user        payment. Payment can take the form of cash payment to a provider        (e.g., credit card, subtraction from a budget), or sending        specified information to an external site (e.g., Nielson-type        information).    -   ii. Quality of Service. Operations may specify particular        quality of service parameters (e.g., by specifying a requested        QoS in MPEG-4), including: requested level of decompression,        requested/required types of display, rendering devices (e.g.,        higher quality loudspeakers, a particular type of game        controller).    -   iii. Time. Operations may be conditioned such that the operation        is only allowed after a particular time, or such that the price        for the operation is tied to the time (e.g., real-time        information at a price, delayed information at a lower price or        free, e.g., allowing controlled copies but only after a        particular date).    -   iv. Display of particular types of content. Operations may be        conditioned on the user authorizing display of certain content        (e.g., the play operation may be free if the user agrees to        allow advertisements to be displayed).

In all of these cases, a rule may be modified by one or more otherrules. A rule may specify that it can be modified by other rules or mayspecify that it is unmodifiable. If a rule is modifiable, it may bemodified by rules sent from other sources. Those rules may be receivedseparately by the user or may be aggregated and received together by theuser.

Data types which may be used in an exemplary MPEG-4 embodiment mayinclude the following:

a. CMP Data Stream.

The CMP-ds is a new elementary stream type that has all of theproperties of an elementary stream including its own CMPO and areference in the object descriptors. Each CMP-ds stream has a series ofone or more CMP Messages. A CMP_Message has four parts:

-   -   1. Count: [1 . . . n] CMPS types supported by this IP ES.        Multiple CMPS systems may be supported, each identified by a        unique type. (There may have to be a central registry of types.)    -   2. CMPS_type_identifiers: [1 . . . n] identifiers, each with an        offset in the stream and a length. The offset points to the byte        in the CMPO where the data for that CMPS type is found. The        length is the length in bytes of this data.    -   3. Data segments: One segment for each of the n CMPS types        encoded in a format that is proprietary to the CMPS supplier.    -   4. CMP_Message_URL: That references another CMP_Message. (This        is in keeping with the standard of using URLs to point to        streams.)

b. CMPO.

The CMPO is a data structure used to attach detailed CMP control toindividual elementary streams. Each CMPO contains:

-   -   1. CMPO_ID: An identifier for the content under control. This        identifier must uniquely identify an elementary stream.    -   2. CMPO_count: [1 . . . n] CMPS types supported by this CMPO.    -   3. CMPS_type_identifiers: [1 . . . n] identifiers, each with an        offset in the stream and a length. The offset points to the byte        in the CMPO where the data for that CMPS type is found. The        length is the length in bytes of this data.    -   4. Data segments: n data segments. Each data segment is in a        format that is proprietary to the CMPS supplier.    -   5. CMPO_URL: An optional URL that references an additional CMPO        that adds information to the information in this CMPO. (This is        a way of dynamically adding support for new CMPSs.)

c. Feedback Event

The feedback events come in two forms: start and end. Each feedbackevent contains three pieces of information:

-   -   1. Elementary_stream_ID    -   2. Time: in presentation time    -   3. Object_instance_number

User Interface.

Commerce Appliance 2301 may include User Interface 2304 designed toconvey control-related information to the user and to receive commandsand information from the user. This interface may include specialpurpose displays (e.g., a light which comes on if a current actionrequires payment), special purpose buttons (e.g., a button which acceptsthe payment or other terms required for display of content), and/orvisual information presented on screen.

Example of Operation in an MPEG-4 Context

1. User selects a particular work or channel. The user may, for example,use a remote control device to tune a digital TV to a particularchannel.

2. Selection of the channel is communicated to a CMPS arrangement, whichuses the information to either download a CCMPO or to identify apreviously downloaded CCMPO (e.g., if the CMPS arrangement is containedin a set-top box, the set-top box may automatically download CCMPOs forevery channel potentially reachable by the box).

3. The CMPS arrangement uses the CCMPO to identify rules associated withall content found on the channel. For example, the CCMPO may specifythat content may only be viewed by subscribers, and may specify that, ifthe user is not a subscriber, an advertisement screen should be put upinviting the user to subscribe.

4. Once rules specified by the CCMPO have been satisfied, the CCMPOspecifies the location of a MCMPO associated with a particular workwhich is available on the channel. The channel CMPO may also supply oneor more keys used for decryption of the MCMPO.

5. The CMPS arrangement downloads the MCMPO. In the case of an MPEG-4embodiment, the MCMPO may be an Elementary Stream. This ElementaryStream must be identifiable at a relatively early stage in the MPEG-4decoding process.

6. The CMPS arrangement decrypts the MCMPO, and determines the rulesused to access and use the content. The CMPS arrangement presents theuser with a set of options, including the ability to view for free withadvertisements, or to view for a price without advertisements.

7. The user selects view for free with advertisements, e.g., byhighlighting and selecting an option on the screen using a remotecontrol device.

8. The CMPS arrangement acquires one or more keys from the MCMPO anduses those keys to decrypt the ESs associated with the video. The CMPSarrangement identifies two possible scene descriptor graphs, one withand one without advertisements. The CMPS arrangement passes the scenedescriptor graph with advertisements through, and blocks the other scenedescriptor graph.

9. The CMPS arrangement monitors the composite and render block, andchecks to determine that the advertisement AVOs have actually beenreleased for viewing. If the CMPS arrangement determines that those AVOshave not been released for viewing, it puts up an error or warningmessage, and terminates further decryption.

CMPS Rights Management in Provider and Distribution Chains

In addition to consumer arrangements, in other embodiments one or moreCMPSs may be used in creating, capturing, modifying, augmenting,animating, editing, excerpting, extracting, embedding, enhancing,correcting, fingerprinting, watermarking, and/or rendering digitalinformation to associate rules with digital information and to enforcethose rules throughout creation, production, distribution, displayand/or performance processes.

In one non-limiting example, a CMPS, a non-exhaustive example of whichmay include a least a secure portion of a VDE node as described in theaforementioned Ginter et al., patent specification, is incorporated invideo and digital cameras, audio microphones, recording, playback,editing, and/or noise reduction devices and/or any other digital device.Images, video, and/or audio, or any other relevant digital informationmay be captured, recorded, and persistently protected using at least oneCMPS and/or at least one CMPO. CMPSs may interact withcompression/decompression, encryption/decryption, DSP, digital toanalog, analog to digital, and communications hardware and/or softwarecomponents of these devices as well.

In another non-exhaustive example, computer animation, special effects,digital editing, color correcting, noise reduction, and any otherapplications that create and/or use digital information may protectand/or manage rights associated with digital information using at leastone CMPS and/or at least one CMPO.

Another example includes the use of CMPSs and/or CMPOs to manage digitalassets in at least one digital library, asset store, film and/or audiolibraries, digital vaults, and/or any other digital content storage andmanagement means.

In accordance with the present applications, CMPSs and/or CMPOs may beused to manage rights in conjunction with the public display and/orperformance of digital works. In one non-exhaustive example, flat panelscreens, displays, monitors, TV projectors, LCD projectors, and/or anyother means of displaying digital information, may incorporate at leastone hardware and/or software CMPS instance that controls the use ofdigital works. A CMPS may allow use only in conjunction with one or moredigital credentials, one example of which is a digital certificate, thatwarrant that use of the digital information will occur in a setting,location, and/or other context for public display and/or performance.Non-limiting examples of said contexts include theaters, bars, clubs,electronic billboards, electronic displays in public areas, or TVs inairplanes, ships, trains and/or other public conveyances. Thesecredentials may be issued by trusted third parties such as certifyingauthorities, non-exhaustive examples of which are disclosed in theaforementioned Ginter '712 patent application.

Additional MPEG-4 Embodiment Information

This work is based on the MPEG-4 description in the version 1 SystemsCommittee Draft (CD), currently the most complete description of theevolving MPEG-4 standard.

This section presents the structural modifications to the MPEG-4 playerarchitecture and discusses the data-lines and the concomitant functionalchanges. FIG. 23 shows the functional components of the original MPEG-4player. Content arrives at Player 2301 packaged into a serial stream(e.g., MPEG-4 Bit Stream 2314). It is demultiplexed via a sequence ofthree demultiplexing stages (e.g., Demux 2305) into elementary streams.There are three principle types of elementary streams: AV Objects (AVO),Scene Descriptor Graph (SDG), and Object Descriptor (OD). These streamsare fed into respective processing elements (e.g., AVO Decode 2307,Scene Descriptor Graph 2306, Object Descriptors 2308). The AVOs are themultimedia content streams such as audio, video, synthetic graphics andso on. They are processed by the player's compression/coding subsystems.The scene descriptor graph stream is used to build the scene descriptorgraph. This tells Composite and Render 2309 how to construct the sceneand can be thought of as the “script.” The object descriptors containdescription information about the AVOs and the SD-graph updates.

To accommodate a CMPS (e.g., CMPS 2302) and to protect contenteffectively, the player structure must be modified in several ways:

-   -   Certain data paths must be rerouted to and from the CMPS    -   Certain buffers in the SDG, AVO decode and Object descriptor        modules must be secured    -   Feedback paths from the user and the composite and render units        to the CMPS must be added

In order for CMPS 2302 to communicate with the MPEG-4 unit, and for itto effectively manage content we must specify the CMPO structure andassociation protocols and we must define the communication protocolsover the feedback systems (from the compositor and the user.)

The structural modifications to the player are shown in FIG. 23. Theprincipal changes are:

-   -   All elementary streams are now routed through CMPS 2302.    -   Direct communication path between Demux 2305 and CMPS 2302.    -   A required “Content Release and Decrypt” Module 2315 in CMPS        2302.    -   The addition of a feedback loop (e.g., Line 2313) from Composite        and Render 2309 to CMPS 2302.    -   Bi-directional user interaction directly with the CMPS 2302,        through Line 2316.

Furthermore, for M4v2P, CMP-objects are preferably associated with allelementary streams. Elementary streams that the author chooses not toprotect are still marked by an “unprotected content” CMPO. The CMPOs arethe primary means of attaching rules information to the content. Contenthere not only refers to AVOs, but also to the scene descriptor graph.Scene Descriptor Graph may have great value and will thus need to beprotected and managed by CMPS 2302.

The direct path from Demux 2305 to CMPS 2302 is used to pass a CMPSspecific header, that potentially contains business model information,that communicates business model information at the beginning of usersession. This header can be used to initiate user identification andauthentication, communicate rules and consequences, and initiateup-front interaction with the rules (selection of quality-of-service(QoS), billing, etc.) The user's communication with CMPS 2302 isconducted through a non-standardized channel (e.g., Line 2316). The CMPSdesigner may provide an independent API for framing these interactions.

Feedback Path 2313 from Composite and Render block 2309 serves animportant purpose. The path is used to cross check that the systemactually presented the user with a given scene. Elementary streams thatare processed by their respective modules may not necessarily bepresented to the user. Furthermore, there are several fraud scenarioswherein an attacker could pay once and view multiple times. The feedbackpath here allows CMPS 2302 to cross check the rendering and therebyperform a more accurate accounting. This feedback is implemented byforcing the Composite and Render block 2309 to issue a start event thatsignals the initiation of a given object's rendering that iscomplemented by a stop event upon termination. The feedback signalingprocess may be made optional by providing a CMP-notification flag thatmay be toggled to indicate whether or not CMPS 2302 should be notified.All CMPOs would be required to carry this flag.

The final modification to the structure is to require that the cleartext buffers in the AVO, SDG and Object Descriptor processors and in theComposite-and-Render block be secured. This is to prevent a pirate fromstealing content in these buffers. As a practical matter, this may bedifficult, since tampering with these structures may well destroysynchronization of the streams. However, a higher state of securitywould come from placing these buffers into a protected processingenvironment.

CMPS 2302 governs the functioning of Player 2301, consistent with thefollowing:

-   -   Communication mechanism between CMPS 2302 and the MPEG-4 player        (via CMPOs)    -   A content release and decryption subsystem    -   Version authentication subsystem    -   Sufficient performance so as not to interfere with the stream        processing in the MPEG-4 components

CMPS 2302 may have a bi-directional side-channel that is external to theMPEG-4 player that may also be used for the exchange of CMP information.Furthermore, the CMPS designer may choose to provide a user interfaceAPI that provides the user with the ability to communicate with thecontent and rights management side of the stream management (e.g.,through Line 2316).

Encrypted content is decrypted and released by CMPS 2302 as a functionof the rules associated with the protected content and the results ofuser interaction with CMPS 2302. Unencrypted content is passed throughCMPS 2302 and is governed by associated rules and user interaction withCMPS 2302. As a consequence of these rules and user interaction, CMPS2302 may need to transact with the SDG and AVO coding modules (e.g.,2310, 2311) to change scene structure and/or the QoS grade.

Ultimately, the CMPS designer may choose to have CMPS 2302 generateaudit trail information that may be sent to a clearinghouse authorityvia CMPS Side Channel Port 2318 or as encrypted content that is packagedin the MPEG-4 bit stream.

The MPEG-4 v1 Systems CD uses the term “object” loosely. In thisdocument, “object” is used to specifically mean a data structure thatflows from one or more of the data paths in FIG. 23.

Using multiple SD-graph update streams, each with its own CMPO, allowsan author to apply arbitrarily specific controls to the SD-graph. Forexample, each node in the SD-graph can be created or modified by aseparate SD-graph update stream. Each of these streams will have adistinct CMPO and ID. Thus, the CMPS can release and decrypt thecreation and modification of each node and receive feedback informationfor each node individually. The practical implications for controllingrelease and implementing consequences should be comparable to having aCMPO on each node of the SD-graph, without the costs of having a CMPO oneach SD-graph node.

Principles consistent with the present invention may be illustratedusing the following examples:

In the first example, there is a bilingual video with either an Englishor French soundtrack. The user can choose during playback to hear eitherthe English or French. The basic presentation costs $1. If the Frenchsoundtrack is presented there is a $0.50 surcharge. If the user switchesback and forth between French and English, during a single viewing ofthe presentation, the $0.50 surcharge will occur only once.

In this example, there will be four elementary streams:

The Scene Description Graph Update stream will have a CMPO. The CMPOwill imply a $1.00 fee associated with the use of the content. The scenedescription graph displays the video, English audio and puts up a buttonthat allows the user to switch to French. If the user clicks thatbutton, the English stops, the French picks up from that point and thebutton changes to a switch-to-English button. (Optionally, there may bea little dialog at the beginning to allow the user to select the initiallanguage. This is all easy to do in the SD graph.)

The Video Stream with the CMPO will say that it can only be released ifthe scene description graph update stream above is released.

The English Audio Stream will be similar to the Video stream.

The French Audio Stream will be similar to the Video stream but there isa $0.50 charge it if is seen in the feedback channel. (The CMPS must tonot count twice if the user switches between the two in a single play ofthe presentation.)

An important requirement is that the ID for the SD-graph update streamappears in the feedback path (e.g., Feedback Path 2313). This is so CMPS2302 knows when the presentation stops and ends so that CMPS 2302 cancorrectly bill for the French audio.

The rules governing the release of the video and audio streams mayinclude some variations. The rules for these streams, for example, maystate something like “if you don't see the id for the scene descriptiongraph update stream X in the feedback channel, halt release of thisstream.” If the main presentation is not on the display, then the videoshould not be. This ties the video to this one presentation. Using thevideo in some other presentation would require access to the originalvideo, not just this protected version of it.

In a second example, an author wants to have a presentation with a freeattract sequence or “trailer”. If the user clicks the correct button thesystem moves into the for-fee presentation, which is organized as a setof “acts”.

Multiple SD-graph update streams may update a scene description graph.Multiple SD-graph update streams may be open in parallel. The timestamps on the ALUs in the streams are used to synchronize andcoordinate.

The trailer and each act are represented by a separate SD-graph updatestream with a separate CMPO. There is likely an additional SD-graphupdate stream that creates a simple root node that is invisible andsilent. This node brings in the other components of the presentation asneeded.

FIG. 29 discloses one exemplary environment for the secure distributionof digital content. As shown in FIG. 29, such an environment includes,for example, a content provider 2902, a control module 2904, and astreamed content appliance or player 2906. Content provider 2902provides to control module 2904 a digital bit stream that includescontent, which is encrypted at least in part, and a secure containerincluding control information designed to control use of the content.The control information includes at least one key suitable fordecryption of at least a portion of the content. Control module 2904 isa protected environment that can function within devices such as set-topboxes, PCs, or other devices for content input or storage, and includesthe ability to manage and protect content, move content to and fromcontent devices, appliances, and other players, and back up and archivedata and other information. One illustrative control module includes aprotected processing environment (PPE) as described in the Ginter '333application. Streamed content player 2906 includes a port configured toaccept a digital bit stream from an external source, such as controlmodule 2904. One illustrative player is an existing MP3 player, modifiedin accordance with the architecture described herein. As discussed indetail below, content player 2906 additionally includes a means foropening secure containers and extracting cryptographic keys, and a meansfor decrypting encrypted portions of the content.

One exemplary embodiment of an architecture for distributing streamedcontent within the environment set forth in FIG. 29 includes at leasttwo components: (1) a streamed content file format, described in detailbelow, for storing and protecting content, and associating protectionrules with it; and (2) a secure protocol, also described in detailbelow, for exchanging security information among content providers,control modules, and players. Such an architecture enables protectedinteractions to, for example, download content from a control module toa content player; transfer content between players, and upload contentfrom a player to a control module.

In accordance with the invention, FIG. 30 discloses one illustrativemanner for downloading content from control module 2904 to contentplayer 2906 utilizing the disclosed architecture. As shown in FIG. 30,the control module and player first engage in the streamed contentprotocol to authenticate each other and establish a secret key forcontent delivery (Step 3000). At Step 3002, control module 3004 performsa transaction to, for example, purchase digital content from contentprovider 3002 following whatever sophisticated business rules contentprovider 3002 requires, and then translates the resulting requirementsinto control information supported in the streamed content file format.The control module then creates a header for the file (protected with anegotiated key), encrypts or otherwise protects the contentappropriately, and then sends the resulting file (a combination of afile header and protected content) to player 2906 (Step 3004). At Step3006, the player receives the file and stores it locally, afterreplacing the header component that used the negotiated temporary keywith an equivalent that uses a secret key known only to the player. Thisre-keying step is advantageous as it avoids exposure of a player'ssecret keys outside the player.

Using the architecture described herein, one skilled in the art willunderstand that transfers between two separate players, for example,will follow a similar path. In this context, however, the header can bemodified to update limit counts or expiration times (e.g., to implementa check-in, check-out procedure), and the file can be re-keyed from thesource player's internal key, to a negotiated temporary key, to theinternal key of the destination player. One skilled in the art willsimilarly understand that the described architecture and file formatsare not limited in their use to particular types of content, particulartypes of control modules, or particular types of players. For example,although object identifiers are carried within the illustrative fileformats described below, the namespace for such identifiers isexplicitly identified to accommodate multiple types of control modules.In addition, the disclosed file formats are lightweight binary formatsthat can be advantageously layered on top of any existing media format,for any type of existing media or content. Accordingly, while the formatcan be used in conjunction with, for example, MP3 files, it can beadapted for any other data format that is represented in a linear file(e.g., other compressed audio formats). Because the file format consistsof a separate header and content object, the format is independent ofany particular content format, and does not change the length orstructure of the content object. One skilled in the art will appreciatethat many features of the illustrative file formats and architecturesdefined herein are optional, and need not be implemented by specificplayers or appliances. Thus, as described herein, an explicit mechanismis provided to mark header components as optional or mandatory. Oneskilled in the art will appreciate that, in an exemplary embodiment ofthe invention, control module 2904 may be included with player 2906.

Compliance profiles that may be defined to promote interoperabilityamong players and other appliances will now be described, followed bydetailed descriptions of illustrative security approaches, file formats,header blocks, protocols, assigned values, and file processing methodsthat may be utilized in accordance with the present invention.

Compliance Profiles

Two compliance approaches, [cp1] and [cp2], are illustratively used inconjunction with the novel file formats and architectures of the presentinvention. The first illustrative compliance profile ([cp1]) has thefollowing characteristics:

-   -   Intended for minimal player devices without support for        cryptography.    -   Supported header components are only Identifier HB, Pad HB,        Trailer HB, and SecurityHeaderV1 (all described in detail        below),    -   Non-cryptographic protection: supports only SecurityHeaderV1.        Thus, no cryptographic algorithms are employed.    -   Minimal player rights management: in the Control Section of the        Security Header, only the player ID and play limit controls are        supported. Other limits (player class, upload, transfer,        time-of-day) are not supported.    -   Transaction data is not required: the Transaction Section of the        Security Header may be left empty, or may be filled in as        desired by the downloading application.

A second compliance profile ([cp2]) may have the followingcharacteristics:

-   -   Intended for minimal player devices, but includes support for        cryptography.    -   Supported header components are only Identifier HB, Pad HB, and        Trailer HB, Key HB, and SecurityHeaderV2,    -   Provides cryptographic protection: supports only        SecurityHeaderV2. Cryptographic algorithms used are        CAST5_(—)56_ECB, CAST5_(—)56_CBC, and XOR_(—)32.    -   Minimal player rights management: in the Control Section of the        Security Header, only the appliance ID and play limit controls        are supported. Other limits (player class, upload, transfer,        time-of-day) are not supported (same as [cp1]).    -   Transaction data is not required: the Transaction Section of the        Security Header may be left empty, or may be filled in as        desired by the downloading application (same as [cp1]).    -   Supported header components are only Identifier HB, Key HB,        SecurityHeaderV2, Pad HB, and Trailer HB.

The following is a description of the characteristics of the Secrecy andIntegrity sections of the Security HeaderV2 (described in detail below)for [cp2].

-   -   The Secrecy Section of the SecurityHeaderV2 is supported, as        described below.    -   The Integrity Section of the SecurityHeaderV2 is not supported.        It may be filled in by the downloading application, but is        ignored by the player device.    -   A single negotiated key is used for transfer of the file to the        player device, and is used to protect a single Key HB block.    -   The key that protects the Key HB block may be identified as        either (A) a temporary (negotiated) key, Key #1 in the Temporary        Key namespace, or as (B) one of possibly several secret keys        embedded in the appliance, Key #1-N in the Music player        namespace.    -   The key that protects the Key HB block is a 56-bit (7 byte) key    -   The algorithm used for encrypting the Key HB block is        CAST5_(—)56_ECB (although DES, or any other suitable algorithm        with 56-bit keys and an 8-byte blocksize, could be substituted        for CAST5 in this Profile).    -   The Header Key that protects the Security Header is a 56-bit key        that is randomly generated by the downloading application.    -   The IV for protecting the Security Header is an 8-byte value        randomly generated by the downloading application.    -   The Security Header is encrypted using the CAST5_(—)56_CBC        algorithm.    -   The Content Key that protects the Critical Blocks is a 56-bit        key that is randomly generated by the downloading application.    -   The IV for protecting the Critical Blocks is an 8-byte value        randomly generated by the downloading application.    -   The algorithm for protecting Critical Blocks is CAST5_(—)56_CBC.    -   The offset, blocksize, and stride for protecting Critical Blocks        are determined by the application.    -   The mask seed for protecting the rest of the Data is a 32-byte        string randomly generated by the downloading application.    -   The algorithm for masking the rest of the Data is XOR_(—)32.    -   The data mask algorithm is never re-seeded (refresh interval is        zero).        Security Approaches

Two levels of security may illustratively be used in conjunction withthe novel file formats and architectures of the present invention. Afirst approach, referred to herein as a cryptographic security approach,employs two mechanisms:

-   -   1. It applies strong cryptography to a small fraction of the        data (the “critical blocks”): on a regular basis, every N_(S)        bytes (the encryption stride), encrypt NCB bytes (the critical        block size). An initial offset N_(O) may also be specified to        indicate where the first critical block is located.        Alternatively, other techniques such as are described below, may        be used to identify the critical blocks.    -   2. It applies a simple XOR mask or other lightweight        cryptographic or masking function to every byte of the data.        When using XOR, the mask has a fixed length, and is repeated        sequentially as needed; for other algorithms, it may take the        form of a cryptographic key or other initialization value. The        mask is refreshed every N_(M) bytes (the mask stride) by        regenerating it using a cryptographic pseudo-random number        generator, or using any other suitable refresh technique, such        as those identified further below. This limits the exposure of        plaintext under any particular mask value.        -   The cryptographic security approach may in addition employ            other algorithms representing different points in the trade            off between performance and security, so that one or more            intermediate algorithms could be used on a greater fraction            of the data than the most costly algorithm, but with less            than complete coverage than the lightest weight algorithm.

The combination of these two mechanisms allows the computational cost ofstrong encryption to be minimized (only a small percentage of the data)while also ensuring that plain text content is never exposed directly(due to the mask). The keys for these two operations are carried in aSecurity Header, described in detail below, which itself is encrypted(and carried in a Security Header Block). The key for the SecurityHeader is, in turn, encrypted in one or more Key Header Blocks, again asis described below. This two-level key management step ensures a uniquekey for the data in any file, and permits files to be efficientlyre-keyed for different environments without also requiring re-encryptionof the data.

Integrity protection is performed in a conventional way using keyed orunkeyed secure hash functions, and can be applied to any or all of threeentities: the Security Header, the set of Header Blocks following theSecurity Header, and the Data itself. As described herein, theencryption process for critical blocks is completely independent of theformat of the underlying data. If the format is known to have a fixedblock size (e.g., MP3 frames), the offset N_(O) and stride N_(S) can beselected so that the critical blocks always include some specificcomponent of the underlying data, such as the MP3 frame headers.

The cryptographic security approach may also define transaction andcontrol attributes that permit a content object to be restricted tospecific players, and that limit the number of operations (e.g., plays,uploads) that can be performed.

A second illustrative security approach, referred to herein as anon-cryptographic security approach, applies a 32-byte XOR mask,repeatedly, to the entire data object. This technique serves to obscurethe data so it cannot be used directly, but is generally more open toattack than is the cryptographic security approach. The XOR mask is,typically, supplied by the intended recipient of the MPRM file throughan additional interaction. The non-cryptographic security approachdefines, however, the same transaction and control attributes as thecryptographic approach.

File Format 3100

FIG. 31 sets forth an illustrative file format 3100, employing thecryptographic security approach, for use in protecting content in theenvironment of FIG. 29. As shown in FIG. 31, file format 3100 comprisesa sequence of several header blocks (HB), followed by a contiguous blockof protected data. More specifically, file format 3100 comprises anIdentification HB 3102 (which indicates that the file is in format3100), a Key HB 3104, a Security HB 3106, a Trailer HB 3108 (which marksthe end of the header and indicates the date size), and contiguous data3110. It is to be understood, however, that while FIG. 31 disclosescertain field sizes or byte lengths as examples of a possibleembodiment, other specific field sizes may be used.

As also shown in FIG. 31, file format 3100 begins with Identification HB3102, and ends with Trailer HB 3108. The data length specified inTrailer HB 3108 may either be the length in bytes of the data followingthe header, or may be all 0xff bytes, indicating that the data continuesuntil the end of the input stream. File format 3100 additionallycontains Security HB 3106. This block, described in detail below,explains how the file data is protected (including both secrecyprotection, or encryption, and integrity protection). The contents ofSecurity HB 3106, except for the type and length of the header block,are encrypted with a unique Header Key. Security HB 3106 also specifieshow all the header blocks following it (including Trailer HB 3108) areprotected.

File format 3100 additionally contains, following Identification HB 3102but before Security HB 3106, at least one Key HB 3104 holding theencrypted Header Key with which the Security HB block data is encrypted.For files that are intended for use by multiple parties (e.g.,personalized for several different players or devices), there may bemultiple Key HBs. The data in the Key HB consists of identificationvalues plus the encrypted Header Key. Non-cryptographic format files donot include any Key HBs.

Each Header Block within file format 3100 has the following structure:

2 bytes Type of Header Block 2 bytes Size (bytes) of Header Block(arbitrary) Header data

Accordingly, each header block is self-identifying. It has a 2-byte typeand a 2-byte size, plus a predetermined amount of header data following.To ensure 4-byte alignment, the size of the header block must be amultiple of 4. In other words, its low-order two bits must be zero. Thesize includes the 4 bytes of identifying information, and has a maximumvalue of 0xFFFC. Thus, each header block is limited to 65528 bytes ofdata.

The low-order two bits of the length may be used to indicate aprocessing type for the Header Block, and are preferably masked off. Insuch an instance, the bits may illustratively be interpreted as follows:

-   -   1x0001 bit: If set, indicates that the HB is mandatory for use,        and that a device which cannot interpret the HB is obliged to        terminate processing on encountering it (and indicate an error).        If clear, indicates that the HB is optional for use, and can be        ignored by a device that does not understand it.    -   0x0002 bit: If set, indicates that the HB is mandatory for        copying, and that a device is obliged to copy its contents        unchanged whenever copying, transferring, or otherwise        replicating the file, if the device cannot interpret the block.        If clear, indicates that the HB should not be preserved on        replication if the device cannot interpret the block. If the        device can interpret the HB, the device is permitted to make an        appropriate decision about whether to preserve it.

File format 3100 may additionally contain one or more Pad HBs (not shownin FIG. 31) which may be use to force other header blocks, or the dataitself, to have a specific alignment with respect to the file origin.More specifically, padding can be used to ensure that the Data isaligned on an appropriate boundary, and likewise to align the SecurityHeader to permit it to be efficiently re-written. Note, however, that toalign the file data at a particular boundary, the final Pad HB blockmust come before Trailer HB 3108; in general, it would typically precedeSecurity HB 3106 to facilitate protection of additional Header Blocks.

File format 3100 may additionally contain other types of header blocks,such as a Firmware HB, typically following Security HB 3106 (which canspecify protection for the additional blocks), as well as other HeaderBlocks carrying information such as additional Rights Managementinformation, digital signatures, and watermark control. These blocksshould, however, be skipped over and not processed by any applicationthat does not understand how to process that particular type. FirmwareHB, Pad HB, as well as those header blocks set forth in FIGS. 31 and 32,may illustratively be defined as follows:

Identification HB 0x0101 HBTypeIdentificationV1 0x000c Size of HB (4 + 8bytes) MPRFile\0 Identification string Pad HB 0x0401 HBTypePadV1 nnnnSize of padding HB (arbitrary) nnnn-4 bytes of zeros TrailerHB 0x0501HBTypeTrailerV1 0x000c Size of HB (4 + 8 bytes) (8 bytes) Size of dataimmediately following KeyHB 0x0201 HBTypeKeyV1 nnnn Size 0x0001 Keynamespace ID nnnn Algorithm identifier nnnn Size of encrypted HeaderKey(16 bytes) Key identifier for encryption (arbitrary) Encrypted HeaderKeySecurity HB (using the cryptographic security approach) 0x0301HBTypeSecurityV1 nnnn Size (arbitrary) Unencrypted SecurityHeaderV1SecurityHB (using the non-cryptographic security approach) 0x0302HBTypeSecurityV2 nnnn Size (arbitrary) Encrypted SecurityHeaderV2FirmwareHB 0x0601 HBFirmware nnnn Size updatetype Type of firmwareupdate block (4 bytes) (arbitrary) Firmware update block(player-dependent)

The above-listed header blocks will now be described in additionaldetail. Referring back to FIG. 31, Key HB 3102 contains, in encryptedform, the temporary key, or Header Key, that encrypts the encryptedSecurity Header. A single, uniquely generated Header Key is used foreach file, but multiple Key HB blocks may be included, each of whichuses different keys to protect the Header Key. Using a 16-byte keyidentifier and a 2-byte namespace identifier, Key HB 3102 alsoidentifies the key that was used to encrypt the Header Key. Itadditionally specifies the algorithm used for the encryption, as wellthe namespace ID (for example, “music player”, “InterTrust”, or“temporary”), which defines how to interpret the key ID. An illustrativekey identifier, in for example a music player namespace, can have threecomponents: a 4-byte player class, a 4-byte key type, and an 8-byteplayer ID. The player class identifies the manufacturer and model ofplayer, while the key types in the music player namespace define whichof possibly several keys contained in the player are used. The player IDis the unique serial number of the player, which is initialized, forexample, in the player's flash memory at the time of manufacture (alongwith, possibly, one or more secret “internal keys”). In the music playernamespace, keys are typically 56-bit (7-byte) values stored in the flashmemory of the player, while the encrypted key size is typically 8 bytes(one block for the algorithm, such as CAST5 or DES). A music player willtypically process a Key HB in the music player namespace by validatingthe player class and key type in the key ID, then matching the player IDagainst its own player ID. If the two values match, it will use one ofits internal keys (as specified) to decrypt the 8-byte block and recoverthe Header Key, which it then uses to decrypt the Security Header.

Security Header Block

Again referring back to FIG. 31, security HB 3106 includes type bytes,size bytes, and a Security Header. The Security Header defines both theprotection (secrecy and integrity) mechanisms for the data and therights management functions applying to use of the data. Logically, theSecurity Header may be divided into four parts:

-   -   Secrecy section, describing how the content data is encrypted;    -   Integrity section, describing how each of the Security Header,        the rest of the protected header, and the content data is        protected for integrity;    -   Control section, which describes the rules governing use of the        file; and a    -   Transaction section, which describes the transaction that caused        the particular file to be created.        Illustratively, two types of security headers may be utilized,        which correspond to the two types of security approaches        previously described:    -   SecurityHeaderV1, which provides minimal non-cryptographic        protection for the data and specifies rules for use.    -   SecurityHeaderV2, which provides cryptographic protection for        the data as well as specifying usage rules and transaction        information.

The cryptographic (V2) security header is more complex, and is definedfirst. The non-cryptographic (V1) header is defined primarily in termsof the V2 header. Both versions define the same set of rights managementfunctions. While these two illustrative security headers are describedherein, one skilled in the art will readily appreciated that otherversions of a Security Header can be defined to accommodate moresophisticated rights management functions than can be expressed infixed-format control and transaction sections. Such versions may useadditional Header Blocks (in the protected section of the header) toinclude additional rights management information (e.g., rules based onidentity characteristics, membership, budget, prior activity).

The SecurityHeaderV2 specifies cryptographic protection and may containsthe following items:

 2 SecurityHeader algorithm (not encrypted) (bytes) 16 SecurityHeader IV(not encrypted) Encrypted below here 32 SecurityHeader Integrity ResultIntegrity checked below here  2 SecurityHeader version (0x0002) nnnSecrecy Data nnn Transaction Data nnn Control Data nnn Integrity Data

The V2 SecurityHeader version is illustratively 0x0002. The SecurityHeader itself is encrypted with the Header Key (carried in the Key HBs).The Security Header IV is used to initialize the decryption algorithm.The data in all other Header Blocks following Security HB 3106 and up tobut not including Trailer HB 3108 are also encrypted with the HeaderKey, and all use the same IV and algorithm as the Security Header.Because the data size may not be a multiple of the cryptographic blocksize, ciphertext-stealing may be used to make the lengths equal.

The Secrecy Data portion of the Security Header defines two items: thestrong encryption that is applied to some parts of the Data, and themask that is applied to all the data. It includes the encryptionspecification for the critical blocks and the masking specification forthe remaining data. One skilled in the art will appreciate that thecritical block encryption can happen before the data masking or after;that is, it can be either the ciphertext or the plaintext that getsmasked. This has to be specified (or made an option) in advance,however, because correct results cannot be obtained without knowing. Itis simply an issue of which order is more optimal for a particularappliance or player, and whether the masking operation is advantageouslypushed into, for example, an audio decoder, rather than imposing such aburdern on the CPU.

In accordance with one embodiment of the invention, critical blockencryption may be specified by the following values (60 bytes total):

2 Critical block encryption Algorithm ID 32 Critical block encryptionKey 16 Critical block IV 2 Critical block size 4 Offset 4 StrideCritical block encryption is performed by encrypting regions whoselength is specified by the critical block size. The first such region islocated at the specified offset from the beginning of the data, and thelater regions are located at the specified stride past the beginning ofthe previous region. The critical block size must be an integralmultiple of the encryption algorithm's native block size. Illustrativevalues might be CAST5_(—)56_CBC for the algorithm (with a native blocksize of 8 bytes), a critical block size of 32 bytes, an offset of zero,and a stride of 1600, ensuring that 2% of the Data is encrypted. If thealgorithm specified operates in a chaining mode, the sequence ofcritical blocks may be treated as a contiguous sequence of plaintext (orciphertext, as appropriate). The feedback from the last encryption inany given critical block region is used to initialize the encryption ofthe first block in the next region.

In one embodiment of the invention, data masking is specified by thefollowing values (54 bytes total):

2 Data Mask Algorithm ID 32 Mask seed 2 Mask refresh algorithm ID 16Mask refresh key 4 Mask refresh intervalData masking is performed by executing the data mask algorithmrepeatedly with the same mask. The mask algorithm has a native blocksize which determines the size of the repeats. If the mask refreshinterval is zero, the mask is specified by the mask seed, and it is usedwithout change for all the data. If the mask refresh interval isnon-zero, the initial mask is the result of applying the specified maskrefresh algorithm to the specified seed and key. This mask is used forall the data bytes in the refresh interval. When the refresh interval isreached, the refresh algorithm is executed again (using the current maskand key) to yield a new mask, which is used until the refresh intervalis completed.

If mask refreshing is enabled, the cryptographic block sizes of the datamask algorithm and the mask refresh algorithm must be equal. The maskalgorithm is illustratively exclusive-OR, with a size of 32 bytes (themaximum possible size for the mask seed).

The Transaction Data portion of the Security Header describes thetransaction that caused the Data to be placed into the MPRF-format file,and may include the following items:

2 Player Namespace ID 8 Player ID 2 Object Namespace ID 16 Data ObjectID 16 Transaction ID 10 Transaction time 2 Transaction type 40 CommentThe Transaction Data is filled in from information available during thetransaction. Depending on how the transaction is performed, however, notall this information may be available. The player namespace ID defineshow to interpret the player ID, which designates the player that wasinvolved in the transaction that resulted in this file being created.The object namespace ID defines how to interpret the othertransaction-related IDs, which represent the “source” of this file. TheData Object ID is the unique ID of the data in the file; it can identifythe object's provider as well as the object. The Transaction ID is theunique ID of the transaction itself, which can be used to locatetransaction records stored elsewhere. The transaction time specifies in,for example, BCD YYYY-MM-DD-HH-MM-SS-hh-ZZZZ format, the time (to thehundredth of a second) at which the transaction took place. BCD formatmay be used to ensure that the value can easily be displayed by a playerof limited computational power. The time is stored in the user's timezone at the time of the transaction; the ZZZZ field indicates theoffset, in minutes, of that time zone from UTC. A negative time zoneoffset may be indicated by a value in the range 4000 to 5159; subtract4000 and negate to get the actual offset. The transaction type specifiesthe type of transaction that resulted in this file being created. Thecomment field is an ASCII string that may be used for any purpose by theapplication that created this file.

The Control Data portion of the Security Header specifies minimal rulesfor content management. It includes a series of flags indicatingoptions, a player ID to which the content may be locked, and limitationson playing, uploading, and transferring (to another player). The ControlData portion may contain the following values:

2 Flags (defined below) 2 Appliance Namespace ID 80 Player ID #1-#10 8Player Class 2 Maximum play count 2 Maximum upload count 2 Maximumtransfer count 6 Activation time (BCD YYYY-MM-DD-HH-MM) 6 Expirationtime (BCD YYYY-MM-DD-HH-MM) 10 Reserved for future use (must be zero)The flags are illustratively defined as follows, and they may be set toindicate that content:

-   0x8000—may be used only on the designated player;-   0x4000—may be used only players of the specified class;-   0x2000—may be used during the specified interval;-   0x1000—is limited in number of plays;-   0x0800—is limited in number of uploads;-   0x0400—is limited in number of transfers;-   0x03FF —(Reserved for future use, must be zero)

If a limit control flag is not set (zero), the corresponding operationis permitted without limitation. A limit value of 0xFFFF indicates thatthe corresponding operation may be performed any number of times. Alimit value of 0x0000 can be used to indicate that the correspondingoperation may not be performed; therefore, to prevent content from beinguploaded, the 0x2000 flag would be set, and the upload limit would havethe value 0x00000000.

If the designated player flag is set, the content may be used only onplayers with IDs that match one of the values in the list of player IDs.An all-zero element in the list of player IDs is ignored. If the playerclass flag is set, the content may be used only on players in the classspecified by the player class ID. If the time limit restriction flag isset, the content may be used only between the specified activation andexpiration times. The activation and expiration time is meaningful onlyon players or other appliances that have an internal clock. Time limitsmay be used to implement a “check-out, check-in” model. Not all playersneed be required to implement all control flags, nor to support non-zerolimit values. If a control flag is found set that the player cannotunderstand or enforce, the content may not be used at all.

In one exemplary embodiment of the invention, the Security Header wouldbe updated as limited operations are performed, decrementing theappropriate limit value. Thus, the Security Header would need to berewritten each time such an operation is performed, and (if supported)its integrity check value would need to be recomputed. Updating theheader in this manner ensures that if the file is subsequently uploadedor transferred, its header correctly indicates the number of operationsremaining.

The Integrity Data portion of the Security Header provides values thatallow the integrity of the Security Header, other Header Blocks, and theData to be verified. These values provide assurance that the relevantdata has not been modified, but do not provide digital signature orproof of origin. Authentication capability may be provided by addinganother Header Block (typically in the unchecked part of the header,before the Security HB block) containing a digital signature. TheIntegrity data may include the following items:

Header Integrity (82 Bytes Total)

2 Algorithm ID 32 Integrity key 16 IV 32 ResultData Integrity (82 Bytes Total)

2 Algorithm ID 32 Integrity key 16 IV 32 ResultSecurityHeader Integrity (50 Bytes Total)

2 Algorithm ID 32 Integrity key 16 IV

Note that the integrity result for the Security Header is part of theSecurity Header itself, and is placed at the very beginning of theSecurity Header block. That field is not included in the integritycalculation for the Security Header, and is filled in after the SecurityHeader is otherwise completed. In turn, the other two integritycalculations must be performed, and results stored here, before theintegrity result is calculated for the Security Header. The integritycheck for the rest of the header is calculated on the encrypted HeaderBlocks following the Security Header, and also includes the Trailer HB(which is not encrypted). Thus, the entire header is generallyconstructed and encrypted before calculating this value. The integritycheck for the data is also calculated on the encrypted representation ofthe data. Different types of integrity validation algorithms (e.g.secure hash, message authentication code) may require a key, an IV, bothor neither.

File Format 3200

FIG. 32 sets forth another illustrative file format 3200, employing thenon-cryptographic security approach, for use in protecting content inthe above-described environment. As shown in FIG. 32, file format 3200comprises a sequence of several header blocks (HB), followed by acontiguous block of protected data. More specifically, file format 3200comprises an Identification HB 3202, a Security HB 3204, a Trailer HB3206, and contiguous data 3208. Identification HB 3202, Trailer HB 3206,and contiguous data 3208 may be identical in format to theircounterparts described in conjunction with FIG. 31. Thenon-cryptographic (V1) security header of Security HB 3204 is moresimple than its counterpart in Security HB 3106. In one embodiment ofthe invention, it provides no Integrity protection and no Secrecyprotection, and contains the following items:

2 SecurityHeaderV1 version (0x0001) 96 Transaction Data 38 Control Data

The Transaction Data and Control Data are the same as forSecurityHeaderV2. However, s 32-byte value is applied to mask the data(except for the initial two bytes of version number) in the SecurityHeader, and also to mask the entire data field. The mask is appliedrepeatedly by XORing with consecutive segments of the header or thedata. The data mask is derived by XORing the 32-byte data mask seedobtained by means outside the scope of this standard (but which, forexample, might be transferred from the receiving device to theoriginating device by a protocol interaction preceding the transfer ofcontent) with a constant value embedded in the implementing components.Typically, the data mask seed will be obtained by requesting it from areceiving player (to which the file is to be delivered), which mayeither supply a constant value or a randomly-generated value. Typicallya file using this approach will have a control flag set to restrict itsuse to the specified appliance. This approach ensures that files createdfor use by one device will be unusable by other appliances. The embeddedconstant ensures that if the data mask seed is delivered through anunsecured protocol, it will not be directly usable if disclosed.Alternatively, the mask seed could be delivered through acryptographically secure protocol, and/or transformed through a strongcryptographic transformation (e.g., a block cipher or secure hash)instead of a simple XOR operation using a constant.

As discussed above, file format 3100 or 3200 may include a Firmware HB.A Firmware HB illustratively contains, in a player-dependent form, anupdate for a player's internal firmware. The firmware update typeidentifies what type of player is to respond to the firmware update;these numbers may be assigned on request by an external authority. Aplayer encountering a Firmware HB should ignore it unless the updatetype matches the type(s) that the player understands. If a match isfound, the player should examine the update contents to determinewhether it needs to be applied (i.e., the update is a newer version thanthe player's existing firmware). If so, it should validate the updateand install it.

Firmware updates are inherently player-specific. Consequently, whether,for example, the update is encrypted, how the update is validated, andhow versions are compared are all issues that are similarlyplayer-specific. What is preferable, however, is that an update have theappropriate matching type. Note that a single logical update may requiremultiple Firmware HBs because the size of the Firmware HB's data islimited to 65524 bytes. It is important to validate an update in acryptographically protected way, entirely independently of theprotection for the rest of the file. Because of this validation, theupdates are typically placed in the unprotected portion of the header,from which they can easily be removed (or inserted) without affectingany other parts of the file. Firmware updates are typically includedonly in files downloaded to a player, rather than being stored at theplayer.

File Processing

Processing a file in file format 3100 or 3200 is inherently sequential.An application examines each Header Block, decides whether to processit, and moves on to the next Header Block until it encounters a TrailerHB, at which point it has located the Data and processes that. Becauseof the sequential nature of such file processing, there are certainordering requirements for the relative position of the Header Blocks,which have been described herein. In addition, because of its sequentialnature, a file formatted using file format 3100 or 3200 can beconstructed from multiple sources concatenated together. It can also bemodified by rearranging, inserting, or deleting Header Blocks, althoughcare must be taken not to do so in a way that affects the protection ofthe protected Header Blocks following the Security Header.

To process the data in a cryptographically-protected file in file format3100, an application may illustratively follows these steps:

-   -   Validate that the file begins with a valid Identification HB    -   Find a Key HB that specifies a key available to the application;        if the Security HB (or the Trailer HB) is encountered before a        suitable Key HB (or before any at all), the data cannot be        accessed.    -   Validate the Key HB to locate the required key. If it is not        available, look for another Key HB.    -   Decrypt the encrypted Header Key using the key specified in the        Key HB.    -   Having found a suitable Key HB block, find the Security HB. If        the Trailer HB is found first, the file is invalid.    -   Decrypt the Security HB using the previously obtained Header        Key, yielding the Security Header.    -   Interpret the Security Header contents to determine how the Data        is protected.    -   Find the Trailer HB to locate the beginning of the data.    -   If header integrity checking is enabled, validate the headers        following the Security HB through and including the Trailer HB.    -   Apply the keys and cryptographic specifications from the        Security Header to decrypt and process the data.

During these steps, the application identifies and skips over any PadHBs it encounters. If it encounters any other types of Header Blocksthat it does understand, it processes them appropriately; otherwise itskips over them. Note that “appropriate” processing may includerejecting the file because it contains a Header Block that theapplication knows about, but is not capable of processingsuccessfully—however, because Header Blocks are typically informational,rather than prescriptive, unfamiliar types can usually be skippedwithout processing.

A non-cryptographic file in, for example, file format 3200, is processedsimilarly, except that there are no Key HBs and no decryptionoperations.

What now follows is a discussion of illustratively assigned values fornamespaces, transaction types, cryptographic algorithms, and otheritems.

Illustrative Assigned Values

The header block type field is a two-byte value. The first byte isnormally used as a format identifier and the second byte as a versionnumber, but application-defined types may apply differentinterpretations as necessary. As but one example, types may be assignedwithin the following ranges:

-   -   0x0001 through 0x3FFF are reserved for definition as part of the        standard architecture.    -   0x4000 through 0xBFFF are reserved for global defined types, and        may be assigned by an agent governing the standard.    -   0xC000 through 0xFFFE are available for arbitrary application        use.    -   0x0000 and 0xFFFF are invalid, and are never to be used.        The following Header Block types may illustratively be defined        as follows:

-   0x0101—Identification block

-   0x0201—KeyHB block

-   0x0301—SecurityHeader block (non-cryptographic)

-   0x0302—SecurityHeader block (cryptographic)

-   0x0401—Padding block

-   0x0501—Trailer block

-   0x0601—Firmware Update block    The following transaction types may illustratively be defined as    follows:

-   0x0001—Transaction involved no exchange of value (“free”)

-   0x0002—Outright purchase

-   0x0003—Limited transfer from other player or container

Each cryptographic algorithm may be defined in terms of severalparameters. For simplicity, all algorithms may have the same set ofparameters, athough some parameters may not be relevant to somealgorithms:

Type. Type of algorithm: Encryption, Unkeyed Hash, Keyed Hash

Block Size. Algorithm's native size of operation. 16 bytes or less forencryption.

Key. Secret key used to run the algorithm. 32 bytes or less.

IV. Initialization vector, used on chaining encryption modes only. 16bytes or less.

Result. Result of a hash or MAC calculation. 32 bytes or less.

If a value is smaller than the field allocated for it (e.g., an 8-byteDES key stored in a 32-byte field), the value is in the leftmost bytesand the remaining bytes are padded with 0x00 bytes. The followingillustrative encryption algorithm IDs may be assigned; each of which isdescribed in further detail below:

-   0x0000—Reserved, error-   0x0001—Function not enabled (used for Key HB)-   0x0002—No encryption (not used for Key HB)-   0x0003—Implicit: key defines its own algorithm (reserved)-   0x0010—XOR_(—)8-   0x0011—XOR_(—)16-   0x0012—XOR_(—)32-   0x0013—XOR_(—)64-   0x0014—XOR_(—)128-   0x0015—XOR_(—)256-   0x0020—DES_(—)56_ECB-   0x0021—DES_(—)56_CBC-   0x0022—DES_(—)56_CBC_MAC-   0x0030—CAST5_(—)56_ECB-   0x0031—CAST5_(—)56_CBC-   0x0032—CAST5_(—)56_CBC_MAC    MPRF_ALG_NO_FUNCTION (0x0001)

This type indicates that the particular security function is not used ornot applicable. It differs from MPRF_ALG_NONE in that it indicates thereis no data to protect, rather than that the data is not encrypted.

Type Not applicable Block size Not applicable Key Not used IV Not usedResult Not usedMPRF_ALG_NONE (0x0002)

This type indicates that the data is not encrypted:

Type Encryption Block size Not applicable Key Not used IV Not usedResult Not usedMPRF_ALG_IMPLICIT (0x0003)

This type indicates that the algorithm is a function of the specifiedkey.

Type Encryption Block size Not applicable Key Not used IV Not usedResult Not used

This type is generally only used in Key HB, and only for keys that havesuch information associated with them.

MPRF_ALG_XOR_(—)8 (0x0010)

This is a masking function using repeated exclusive-OR with the same8-bit key on successive data blocks:

Type Encryption Block size 1 byte Key 1 byte IV Not used Result Not usedMPRF_ALG_XOR_(—)16 (0x0011)

This is a masking function using repeated exclusive-OR with the same16-bit key on successive data blocks (that is, it masks every byte witha constant value):

Type Encryption Block size 2 bytes Key 2 bytes IV Not used Result NotusedMPRF_ALG_XOR_(—)32 (0x0012)

This is a masking function using repeated exclusive-OR with the same32-bit key on successive data blocks:

Type Encryption Block size 4 bytes Key 4 bytes IV Not used Result NotusedMPRF_ALG_XOR_(—)64 (0x0013)

This is a masking function using repeated exclusive-OR with the same64-bit key on successive data blocks:

Type Encryption Block size 8 bytes Key 8 bytes IV Not used Result NotusedMPRF_ALG_XOR_(—)128 (0x0014)

This is a masking function using repeated exclusive-OR with the same128-bit key on successive data blocks:

Type Encryption Block size 16 bytes Key 16 bytes IV Not used Result NotusedMPRF_ALG_XOR_(—)256 (0x0015)

This is a masking function using repeated exclusive-OR with the same256-bit key on successive data blocks:

Type Encryption Block size 32 bytes Key 32 bytes IV Not used Result NotusedMPRF_ALG DES_(—)56_ECB (0x0020)

This is the standard DES algorithm operating in Electronic Code Bookmode:

Type Encryption Block size 8 bytes Key 8 bytes (DES format, with parityignored) IV Not used Result Not usedMPRF_ALG_DES_(—)56_CBC (0x0021)

This is the standard DES algorithm operating in Cipher Block Chainingmode:

Type Encryption Block size 8 bytes Key 8 bytes (DES format, with parityignored) IV 8 bytes Result Not usedMPRF_ALG_DES_(—)56_CBC_MAC (0x0022)

This is the standard DES algorithm operating in Cipher Block Chainingmode used to calculate a Message Authentication Code:

Type Keyed Hash Block size 8 bytes Key 8 bytes (DES format, with parityignored) IV 8 bytes Result 8 bytesMPRF_ALG_CAST5_(—)56_ECB (0x0030)

This is the standard CAST5 algorithm (see RFC-2144) operating inElectronic Code Book mode:

Type Encryption Block size 8 bytes Key 7 bytes, padded with 0x00 onright IV Not used Result Not usedMPRF_ALG_CAST5_(—)56_CBC (0x0031)

This is the standard CAST5 algorithm operating in Cipher Block Chainingmode:

Type Encryption Block size 8 bytes Key 7 bytes, padded with 0x00 onright IV 8 bytes Result Not usedMPRF_ALG_CAST5_(—)56_CBC_MAC (0x0032)

This is the standard CAST5 algorithm operating in Cipher Block Chainingmode used to calculate a Message Authentication Code:

Type Keyed Hash Block size 8 bytes Key 7 bytes, padded with 0x00 onright IV 8 bytes Result 8 bytesLow-Level Data Formats

The following low-level Data Formats may be used in accordance with theinvention, although those skilled in the art will appreciate that manyother data formats may be utilized in the architecture described herein.So, for example, all integers in the file formats may be stored “bigendian”, with the high-order byte at position zero and the low-orderbyte at the other end of the field. Except as noted elsewhere herein,all integer values may be unsigned. When a field (notably, acryptographic value) is larger than the value it needs to hold, thevalue may be left-aligned in the field, and padded on the right with0x00 bytes. When a value (e.g., an encrypted cryptographic key) issmaller than the cryptographic block size used to encrypt it, value maybe left-aligned in the field, and padded on the right with 0x00 bytesbefore being encrypted. The zeros are ignored on decryption. HeaderBlocks (and thus data) may advantageously be required to be aligned on4-byte boundaries within the file. This alignment ensures that storagefor the type and length fields is always in a contiguous 4-byte unit,facilitating processing even if the file is stored in non-contiguousblocks. To implement this alignment restriction, the length field of aHeader Block must be a multiple of 4; in the event that the data in theHeader Block requires a length that is not a multiple of 4, that must beindicated by a length (or adjustment) field stored in the Header Block'sdata. In an alternative embodiment, the length field could have thevalue length/4, and require multiplication (shift) to determine theactual length. That would allow larger Header Blocks, but wouldcomplicate the basic processing loop somewhat because of the need tohandle length values larger than are representable in 16 bits. Alsoalternatively, the low-order bits of the length could be used as flags,which would provide for an aesthetically pleasing implementation of themandatory/optional processing option. BCD values (e.g., the TransactionTime field of the SecurityHeader) may also be stored “big endian”, withthe high-order digit of a pair in the high-order 4 bits of the bits.

Streamed Content Protocols

The following protocol is one embodiment of, consistent with theinvention, a simple authentication and key negotiation protocol for useamong, for example, control modules and content players. Eachparticipant (module or player) has built into it the public (signaturevalidation) key of a predetermined licensing agent or authority, forexample. Each participant has its own public signature key, signed bythe licensing authority, and a correspnding private (signing) key. Eachparticipant also has built into it the global public key negotiationkey.

The public key and key negotiation key should be constant for alldevices with the architecture described herein; the device public key isunique to each device. The protocol may illustratively use signedDiffie-Hellman key exchange (“station-to-station protocol”) to negotiatea session key that can be used for subsequent transfers of files in, forexample, format 3100 or 3200. While this protocol is well suited for usewith players of limited processing capability, because it usesfixed-format raw representations of keys and signatures rather thanusing X.509 certificates (it is to be understood that players can beinitialized with data from such certificates), it may advantageouslyused with any player or appliance.

The protocol requires that each participant have several differentinstances of the various keys, to permit immediate response to keycompromises. Player firmware updates can also be used to update keysover the longer term. There is only one level of public keyinfrastructure in this protocol, and all public keys may be signeddirectly by a predetermined licensing authority. A licensee can generatea large batch of key pairs, and send the public parts to the licensingauthority for signing, or can simply request that the authority generatethem and send the complete key pairs (and signatures) back. Eithermethod may be used consistently with the present invention, althoughthey have different security characteristics.

Yet another exemplary embodiment of a content-transfer protocol is asfollows. In this embodiment, the assumption is made that the originatingdevice, such as a media player device, has a file, protected with asecret key known only to that device, and that the receiving device hasa similar secret key known to it. One device wishes to send the file tothe other, without either device revealing their secret keys. In such aninstance, the devices can exchange a file securely using the followingprocess:

-   -   Negotiate a session key (using Diffie-Hellmann or a similar        cryptographic protocol)    -   Optionally, each device may authenticate the other (using        digital signatures or similar cryptographic techniques)    -   The sending device can re-key the file using the negotiated        session key, by replacing or adding a Key HB in the file.    -   The sending device transmits the file to the receiving device;        because the file is cryptographically protected, the medium of        transfer need not be protected.    -   The receiving device re-keys the file by replacing the KeyHB        specifying the negotiated session key with a KeyHB using its own        secret key.    -   The receiving device stores the file.

The file exchange process requires temporary storage only for the KeyHBthat is used to hold the temporary key, not for the rest of the headeror the file content. One skilled in the art will appreciate that thesame file exchange protocol can be used to transfer a file between adevice and a rights management system (as is described in theincorporated references.). The rights management system can additionallyinterpret rights management information at the originating end tospecify rules and controls to be embedded in the file header. As areceiver, the rights management system can construct new rightsmanagement information from rules and controls in the received file.

When a rights management system includes rules and controls, andtransaction information, in the header of a protected file, the controlscan specify a subset of the originating object's rights managementinformation. For example, the following can be specified:

-   -   A limitation on the number of times a protected media file may        be played    -   A limitation on the number of times a protected file may be        uploaded back out of the device to a host system    -   A limitation on the number of times a protected file may be        transferred from one device to another    -   A limitation on the time period during which the protected file        may be used (both beginning and end)    -   A constraint limiting use of the file to a particular device    -   A constraint limiting use of the file to a class of devices    -   A constraint limiting use of the file to devices owned by a        particular person    -   or, in general, any rule or set of rules as may be determined        from a set of rights management information associated with the        original object.

Controls and limits may be specified in multiples or in combination.Transaction information may be included to identify the rightsmanagement transaction that resulted in creating the file, and recordedin the header for auditing or tracking purposes. Such information mayinclude:

-   -   Unique transaction ID    -   Transaction time    -   Originating object ID    -   User ID of transaction    -   Device ID of intended recipient device    -   Transaction price    -   Transaction type    -   Transaction report (audit) recipient(s)    -   or, in general, any other information that may serve an auditing        or tracking purpose.

Consistent with the invention, various embodiments of a novel fileformat have been described. These formats are advantageous due to, interalia, the following. They support strong cryptographic protection, whileallowing for a small, fast runtime implementation. The format forcarrying header information is highly efficient for processing bydevices with limited processing resources. It allows an arbitrarysequence of self-identifying header components to be associated with aprotected object, such that individual components can be located,inserted, removed, and rearranged with minimal cost. The format allowsfor integrity and secrecy protection of selected header components bydividing the components into two groups (protected, non-protected), andalso ensures that transfer protocols need not understand the underlyingcontent format. The format allows for padding to align any desiredcomponents, or the content data, on desired boundaries. The formatallows for the header to be processed efficiently even if stored indiscontiguous blocks, by guaranteeing that the type/length fields arealways located in a contiguous 4-byte region. The protected file and/orits header may be protected for integrity by conventional cryptographictechniques (e.g., cryptographic hash, message authentication code). Thisprotection is specified in the security-critical part of the header, andis facilitated by the header structure.

The multi-level keying scheme described herein is advantageous in thatit uses a unique Content Key (and Content Mask) for protecting thecontent object. These keys are stored (and protected) in the SecurityHeader, which is in turn protected by a unique Header Key. The HeaderKey, in turn, is stored in one or more Key HBs, which are protected byTransport Keys that are identified in the header (in the Key HBs), butnot stored in the header. This scheme allows the file to be re-keyed byreplacing (or adding) a new Key HB, without changing any other part ofthe header or the data. This scheme also allows the header to bere-keyed without changing the data, and allows the content to bere-keyed without changing or even knowing the keys that protect theHeader Key in the Key HBs. Such re-keying may be appropriate orpreferred as a standard part of redistribution. This scheme isadditionally advantageous as it uses unique keys for the content and forthe header to avoid exposure of long-term visible keys.

The cryptographic content security scheme described herein isadvantageous as it employs two algorithms together: one, an expansive,strong algorithm (e.g., a block cipher such as DES or CAST5), encryptsonly “critical blocks” of the content. The other, a low-cost but weakeralgorithm (e.g., an XOR function or a fast stream cipher), encrypts ormasks the entire content. Depending on the needs of the application, thelow-cost step can take place before the stronger step (thus masking theplaintext before its critical blocks are encrypted), or can take placeafterward. One skilled in the art will appreciate that the appropriateorder may be governed by efficiency considerations in using theplaintext (as input to an audio decoder, for example). The criticalblocks selected for strong encryption can be selected in a variety ofways, including but not limited to:

-   -   Starting at some specified offset into the content, and locating        critical blocks at fixed intervals beginning from that offset;    -   Interpreting the content format, and locating specific data        elements to be strongly encrypted, such as the headers for MP3        audio frames;    -   Using a pseudo-random number generator (not necessarily a secure        one) to randomly select the locations of a certain percentage of        blocks out of the content (possibly encrypting some blocks, or        parts of blocks, multiple times, but reversing the multiple        applications during decryption);    -   Using a pseudo-random number generator (as above) to determine        intervals between the critical blocks, thus avoiding multiple        encryption;    -   Starting by encrypting a block at a specified location, extract        a value from each encrypted block (after encryption) as a        pseudo-random number generator to specify an offset, interval,        or other locator for the next critical block to be encrypted.

Chaining encryption modes can be employed by treating the sequence ofcritical blocks as a single contiguous sequence of plaintext, andcarrying the feedback variable from the end of one such block to thebeginning of another. The above methods leave the size of the content,and offset locations and alignment within it, unchanged. This isimportant for any sort of random access application (although certainmethods make random access more difficult because the critical blocksare located by a pseudo-random process). It is also possible to modifythe content by inserting additional information into the content thatcan specify critical block locations, protection parameters, or otherinformation. The low-cost masking algorithm can always use the same key(mask), applying it repeatedly for the entire content object. Themasking can also be re-keyed at intervals throughout the content,performing a relatively expensive re-keying operation (such as using acryptographically secure pseudo-random number generator) onlyoccasionally. Re-keying can be periodic, or determined on apseudo-random basis using techniques like those for locating criticalblocks.

One skilled in the art will appreciate that, utilizing theabove-described architectures and file formats, and utilizing aprotected processing environment (PPE) or other control module to governcontent in accordance with rules, a secure content extraction method andapparatus can be implemented as follows.

Content with an identifying mark, such as CD music with an embeddedidentification means (e.g., a digitally attached or watermarked ISRC, orthe content itself) may be input by a user into a secure contentextractor or ripper (which is illustratively a version of a non-ripper,modified in accordance herewith, that extracts PCM samples from acompact disk onto a computer hard disk, and subsequently converts thesamples into a compressed format such as MP3. The secure extractorexamines the content and extracts the identification means. Theextractor may then reference a database (which may be a secure databaseas is described in the Ginter '333 application) that lists or otherwiseidentifies all previously ripped or extracted content. If the contenthas been previously extracted, then this fact can be communicated backto the user, who may also be informed that the content cannot be ripped.This fact may be additionally communicated to third parties for thepurpose of, for example, fraud detection.

If the content has not been previously extracted, then the extractor mayobtain the content from its original format (such as a music CD), andsecure it within a new content format. Secure formats include, forexample, an MP3 audio file in file format 3100, file format 3200, or,more generally, a Digibox. The ripper may also communicate with thesecure database to ensure that the newly-extracted content is logged as“extracted”.

One skilled in the art will appreciate that the following protocol isalso enabled by the novel architectures and file formats disclosedherein. As set forth in FIG. 29, a PPE or control module 2904 may beconnected to one or more content players 2906. Because, content players2906 may support one or more content formats (e.g., MP3), control module2904 can be configured to maintain a list of associated player devices,and the formats they support.

Content, such as music, and rules may be securely provided to controlmodule 2904 by content provider 2902 in, for example, a DigiBox.Utilizing its list of associated player devices, and the rules providedwith the content, control module 2904 can determine: (a) if a particularplayer device supports the content format; and (b) if not, whether therules allow for reformatting of the content to a supported format. Ifthe rules permit reformatting, control module 2904 extracts the musiccontent from the DigiBox and transforms the content into a supportedformat using, for example, a mask. Such masks may be, for example,resident in control module 2904 or delivered in a DigiBox from apredetermined mask clearinghouse.

The foregoing description of implementations of the invention has beenpresented for purposes of illustration and description. It is notexhaustive and does not limit the invention to the precise formdisclosed. Modifications and variations are possible in light of theabove teachings or may be acquired from practicing of the invention. Forexample, the described implementation includes software but the presentinvention may be implemented as a combination of hardware and softwareor in hardware alone. The invention may be implemented with bothobject-oriented and non-object-oriented programming systems. The scopeof the invention is defined by the claims and their equivalents.

1. A streaming media player providing content protection and digitalrights management, including: a port configured to receive a digital bitstream, the digital bit stream comprising at least two sub-streams whichhave been mixed together, the digital bit stream including: contentwhich is encrypted at least in part, and control information forcontrolling use of the content, the control information including atleast one key suitable for decryption of at least a portion of thecontent, and a first rule or rule set including at least one rulespecifying that the content can only be decrypted on a system having apredefined system identifier; a control arrangement including: means forextracting cryptographic keys from the digital bit stream; a second ruleor rule set governing at least one aspect of usage of at least onesub-stream or object, wherein the second rule or rule set includes atleast one rule stored in a non-volatile memory internally integratedwith the player; and means for enforcing the first rule or rule set andthe second rule or rule set, the means for enforcing including means forselectively passing at least one key to a stream controller inaccordance with the first rule or rule set; a demux designed to separateand route the sub-streams; a decompression unit configured to decompressat least one of the sub-streams, the decompression unit and the demuxbeing connected by a pathway for the transmission of information; arendering unit designed to process decompressed content information forrendering; and a stream controller operatively connected to thedecompression unit and the control arrangement, the stream controllerincluding decryption functionality configured to decrypt at least aportion of a sub-stream based on at least one key passed from thecontrol arrangement and pass the decrypted sub-stream to thedecompression unit.
 2. The player of claim 1, wherein the second rule orrule set includes at least one rule that is delivered from an externalsource.
 3. The player of claim 1, wherein the second rule or rule setspecifies conditions under which the at least one sub-stream or objectmay be decrypted.
 4. The player of claim 1, wherein the second rule orrule set governs at least one aspect of access to the at least onesub-stream or object.
 5. The player of claim 1, wherein the at least oneaspect of usage includes making copies of the at least one sub-stream orobject.
 6. The player of claim 1, wherein the at least one aspect ofusage includes transmitting the at least one sub-stream or objectthrough a digital output port.
 7. The player of claim 1, wherein thesecond rule or rule set specifies that the at least one sub-stream orobject can be transferred to a second device, but rendering of the atleast one sub-stream or object must be disabled in the streaming mediaplayer prior to or during the transfer.
 8. The player of claim 7,wherein the second device includes rendering capability, lacks at leastone feature present in the streaming media player, and is at leastsomewhat more portable than the streaming media player.
 9. The player ofclaim 1, wherein the first rule or rule set controls at least one aspectof operation of the second rule or rule set.
 10. The player of claim 1,wherein the at least one aspect of usage includes use of at least onebudget.
 11. The player of claim 1, wherein the at least one aspect ofusage includes a requirement that audit information be provided.
 12. Theplayer of claim 1, wherein the second rule or rule set is configured tocondition viewing information in at least one sub-stream upon viewinginformation in another sub-stream.
 13. The player of claim 12, whereinthe at least one sub-stream comprises an advertisement.
 14. A streamingmedia player providing content protection and digital rights management,including: a port configured to receive a digital bit stream, thedigital bit stream including: content which is encrypted at least inpart, at least two sub-streams which have been muxed together, at leastone of the sub-streams including compressed information, and a securecontainer including control information for controlling use of thecontent, including at least one key suitable for decryption of at leasta portion of the content; a control arrangement including: means foropening secure containers and extracting cryptographic keys, means fordecrypting the encrypted portion of the content; and a rule or rule setgoverning at least one aspect of usage of at least one sub-stream orobject, wherein the rule or rule set is configured to conditionallyrequire viewing of information in at least one sub-stream in order toview information in another sub-stream; a demux designed to separate androute the sub-streams; a decompression unit and the demux beingconnected by a pathway for the transmission of information; a renderingunit designed to process decompressed content information for rendering;and a stream controller operatively connected to the decompression unitand the control arrangement, the stream controller including decryptionfunctionality configured to decrypt at least a portion of a sub-streambased on at least one key passed from the control arrangement and passthe decrypted sub-stream to the decompression unit.